21001054564 has 12 divisors (see below), whose sum is σ = 42002109184. Its totient is φ = 9000451944.

The previous prime is 21001054517. The next prime is 21001054583. The reversal of 21001054564 is 46545010012.

21001054564 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 750037663 = 21001054564 / (2 + 1 + 0 + 0 + 1 + 0 + 5 + 4 + 5 + 6 + 4).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 375018804 + ... + 375018859.

Almost surely, 2^21001054564 is an apocalyptic number.

It is an amenable number.

21001054564 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21001054564 is a wasteful number, since it uses less digits than its factorization.

21001054564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750037674 (or 750037672 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 28.

Adding to 21001054564 its reverse (46545010012), we get a palindrome (67546064576).

The spelling of 21001054564 in words is "twenty-one billion, one million, fifty-four thousand, five hundred sixty-four".