3993646524921 has 27 divisors (see below), whose sum is σ = 5782811498373. Its totient is φ = 2655888219000.

The previous prime is 3993646524899. The next prime is 3993646524929. The reversal of 3993646524921 is 1294256463993.

The square root of 3993646524921 is 1998411.

It is a perfect power (a square), and thus also a powerful number.

3993646524921 is a `hidden beast` number, since 3 + 9 + 9 + 364 + 6 + 5 + 249 + 21 = 666.

It is not a de Polignac number, because 3993646524921 - 2²⁷ = 3993512307193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3993646524929) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 4502419540 + ... + 4502420426.

Almost surely, 2^{3993646524921} is an apocalyptic number.

3993646524921 is the 1998411-st square number.

3993646524921 is the 999206-th centered octagonal number.

It is an amenable number.

3993646524921 is a deficient number, since it is larger than the sum of its proper divisors (1789164973452).

3993646524921 is an frugal number, since it uses more digits than its factorization.

3993646524921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3282 (or 1641 counting only the distinct ones).

The product of its digits is 75582720, while the sum is 63.

The spelling of 3993646524921 in words is "three trillion, nine hundred ninety-three billion, six hundred forty-six million, five hundred twenty-four thousand, nine hundred twenty-one".