645231540 has 96 divisors (see below), whose sum is σ = 1849309056. Its totient is φ = 168030720.

The previous prime is 645231511. The next prime is 645231569. The reversal of 645231540 is 45132546.

It is an interprime number because it is at equal distance from previous prime (645231511) and next prime (645231569).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 645231498 and 645231507.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1052274 + ... + 1052886.

It is an arithmetic number, because the mean of its divisors is an integer number (19263636).

Almost surely, 2^645231540 is an apocalyptic number.

645231540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645231540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (924654528).

645231540 is an abundant number, since it is smaller than the sum of its proper divisors (1204077516).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645231540 is a wasteful number, since it uses less digits than its factorization.

645231540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1009 (or 1007 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

The square root of 645231540 is about 25401.4082286790. The cubic root of 645231540 is about 864.1156341718.

The spelling of 645231540 in words is "six hundred forty-five million, two hundred thirty-one thousand, five hundred forty".