521997645 has 16 divisors (see below), whose sum is σ = 899442432. Its totient is φ = 256983360.

The previous prime is 521997629. The next prime is 521997653. The reversal of 521997645 is 546799125.

It is not a de Polignac number, because 521997645 - 2⁴ = 521997629 is a prime.

It is a super-3 number, since 3×521997645³ (a number of 27 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 521997594 and 521997603.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1338261 + ... + 1338650.

It is an arithmetic number, because the mean of its divisors is an integer number (56215152).

Almost surely, 2^521997645 is an apocalyptic number.

It is an amenable number.

521997645 is a deficient number, since it is larger than the sum of its proper divisors (377444787).

521997645 is a wasteful number, since it uses less digits than its factorization.

521997645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2676932.

The product of its digits is 680400, while the sum is 48.

The square root of 521997645 is about 22847.2677797587. The cubic root of 521997645 is about 805.1735772710.

The spelling of 521997645 in words is "five hundred twenty-one million, nine hundred ninety-seven thousand, six hundred forty-five".