6398821564 has 6 divisors (see below), whose sum is σ = 11197937744. Its totient is φ = 3199410780.

The previous prime is 6398821553. The next prime is 6398821613. The reversal of 6398821564 is 4651288936.

It is a super-2 number, since 2×6398821564² = 81889834815822812192, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 799852692 + ... + 799852699.

Almost surely, 2^6398821564 is an apocalyptic number.

It is an amenable number.

6398821564 is a deficient number, since it is larger than the sum of its proper divisors (4799116180).

6398821564 is a wasteful number, since it uses less digits than its factorization.

6398821564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1599705395 (or 1599705393 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 52.

The square root of 6398821564 is about 79992.6344359279. The cubic root of 6398821564 is about 1856.5215719632.

The spelling of 6398821564 in words is "six billion, three hundred ninety-eight million, eight hundred twenty-one thousand, five hundred sixty-four".