21123551051 has 16 divisors (see below), whose sum is σ = 22034268000. Its totient is φ = 20236539648.

The previous prime is 21123550967. The next prime is 21123551143. The reversal of 21123551051 is 15015532112.

It is a cyclic number.

It is not a de Polignac number, because 21123551051 - 2¹⁴ = 21123534667 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21123551051.

It is not an unprimeable number, because it can be changed into a prime (21123551851) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 443255 + ... + 488591.

It is an arithmetic number, because the mean of its divisors is an integer number (1377141750).

Almost surely, 2^21123551051 is an apocalyptic number.

21123551051 is a deficient number, since it is larger than the sum of its proper divisors (910716949).

21123551051 is a wasteful number, since it uses less digits than its factorization.

21123551051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45598.

The product of its (nonzero) digits is 1500, while the sum is 26.

The spelling of 21123551051 in words is "twenty-one billion, one hundred twenty-three million, five hundred fifty-one thousand, fifty-one".