1645501620 has 96 divisors (see below), whose sum is σ = 5277742848. Its totient is φ = 375247872.

The previous prime is 1645501619. The next prime is 1645501661. The reversal of 1645501620 is 261055461.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 187654 + ... + 196226.

It is an arithmetic number, because the mean of its divisors is an integer number (54976488).

Almost surely, 2^1645501620 is an apocalyptic number.

1645501620 is a gapful number since it is divisible by the number (10) 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 1645501620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2638871424).

1645501620 is an abundant number, since it is smaller than the sum of its proper divisors (3632241228).

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

1645501620 is a wasteful number, since it uses less digits than its factorization.

1645501620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9049 (or 9047 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 1645501620 is about 40564.7830020080. The cubic root of 1645501620 is about 1180.5909182421.

The spelling of 1645501620 in words is "one billion, six hundred forty-five million, five hundred one thousand, six hundred twenty".