21253774087 has 16 divisors (see below), whose sum is σ = 26164918080. Its totient is φ = 16812041472.

The previous prime is 21253774043. The next prime is 21253774093. The reversal of 21253774087 is 78047735212.

It is a cyclic number.

It is not a de Polignac number, because 21253774087 - 2¹⁵ = 21253741319 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253774037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 374733 + ... + 427705.

It is an arithmetic number, because the mean of its divisors is an integer number (1635307380).

Almost surely, 2^21253774087 is an apocalyptic number.

21253774087 is a deficient number, since it is larger than the sum of its proper divisors (4911143993).

21253774087 is a wasteful number, since it uses less digits than its factorization.

21253774087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57402.

The product of its (nonzero) digits is 658560, while the sum is 46.

The spelling of 21253774087 in words is "twenty-one billion, two hundred fifty-three million, seven hundred seventy-four thousand, eighty-seven".