21102023551 has 8 divisors (see below), whose sum is σ = 25535221920. Its totient is φ = 17023481088.

The previous prime is 21102023479. The next prime is 21102023581. The reversal of 21102023551 is 15532020112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21102023551 - 2²³ = 21093634943 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102023581) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88663846 + ... + 88664083.

It is an arithmetic number, because the mean of its divisors is an integer number (3191902740).

Almost surely, 2^21102023551 is an apocalyptic number.

21102023551 is a deficient number, since it is larger than the sum of its proper divisors (4433198369).

21102023551 is a wasteful number, since it uses less digits than its factorization.

21102023551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177327953.

The product of its (nonzero) digits is 600, while the sum is 22.

Adding to 21102023551 its reverse (15532020112), we get a palindrome (36634043663).

The spelling of 21102023551 in words is "twenty-one billion, one hundred two million, twenty-three thousand, five hundred fifty-one".