645597942 has 64 divisors (see below), whose sum is σ = 1482105600. Its totient is φ = 185655680.

The previous prime is 645597919. The next prime is 645597943. The reversal of 645597942 is 249795546.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645597943) by changing a digit.

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, 110068 + ... + 115784.

It is an arithmetic number, because the mean of its divisors is an integer number (23157900).

Almost surely, 2^645597942 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645597942, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (741052800).

645597942 is an abundant number, since it is smaller than the sum of its proper divisors (836507658).

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

645597942 is a wasteful number, since it uses less digits than its factorization.

645597942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5821.

The product of its digits is 2721600, while the sum is 51.

The square root of 645597942 is about 25408.6194430158. The cubic root of 645597942 is about 864.2791691537.

The spelling of 645597942 in words is "six hundred forty-five million, five hundred ninety-seven thousand, nine hundred forty-two".