1645732520 has 32 divisors (see below), whose sum is σ = 3707548200. Its totient is φ = 657466368.

The previous prime is 1645732499. The next prime is 1645732531. The reversal of 1645732520 is 252375461.

It can be written as a sum of positive squares in 4 ways, for example, as 1224580036 + 421152484 = 34994^2 + 20522^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6932 + ... + 57788.

Almost surely, 2^1645732520 is an apocalyptic number.

1645732520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1645732520 is an abundant number, since it is smaller than the sum of its proper divisors (2061815680).

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

1645732520 is a wasteful number, since it uses less digits than its factorization.

1645732520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51677 (or 51673 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 35.

The square root of 1645732520 is about 40567.6289669485. The cubic root of 1645732520 is about 1180.6461366003.

The spelling of 1645732520 in words is "one billion, six hundred forty-five million, seven hundred thirty-two thousand, five hundred twenty".