21056512654 has 4 divisors (see below), whose sum is σ = 31584768984. Its totient is φ = 10528256326.

The previous prime is 21056512651. The next prime is 21056512657. The reversal of 21056512654 is 45621565012.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21056512651) and next prime (21056512657).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056512651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5264128162 + ... + 5264128165.

It is an arithmetic number, because the mean of its divisors is an integer number (7896192246).

Almost surely, 2^21056512654 is an apocalyptic number.

21056512654 is a deficient number, since it is larger than the sum of its proper divisors (10528256330).

21056512654 is a wasteful number, since it uses less digits than its factorization.

21056512654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10528256329.

The product of its (nonzero) digits is 72000, while the sum is 37.

The spelling of 21056512654 in words is "twenty-one billion, fifty-six million, five hundred twelve thousand, six hundred fifty-four".