21075451655 has 32 divisors (see below), whose sum is σ = 27408844800. Its totient is φ = 15516404992.

The previous prime is 21075451591. The next prime is 21075451679. The reversal of 21075451655 is 55615457012.

It is not a de Polignac number, because 21075451655 - 2⁶ = 21075451591 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 285851 + ... + 351939.

It is an arithmetic number, because the mean of its divisors is an integer number (856526400).

Almost surely, 2^21075451655 is an apocalyptic number.

21075451655 is a deficient number, since it is larger than the sum of its proper divisors (6333393145).

21075451655 is a wasteful number, since it uses less digits than its factorization.

21075451655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66223.

The product of its (nonzero) digits is 210000, while the sum is 41.

The spelling of 21075451655 in words is "twenty-one billion, seventy-five million, four hundred fifty-one thousand, six hundred fifty-five".