21136555451 has 4 divisors (see below), whose sum is σ = 23058060504. Its totient is φ = 19215050400.

The previous prime is 21136555423. The next prime is 21136555457. The reversal of 21136555451 is 15455563112.

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

It is a cyclic number.

It is not a de Polignac number, because 21136555451 - 2²² = 21132361147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21136555457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 960752510 + ... + 960752531.

It is an arithmetic number, because the mean of its divisors is an integer number (5764515126).

Almost surely, 2^21136555451 is an apocalyptic number.

21136555451 is a deficient number, since it is larger than the sum of its proper divisors (1921505053).

21136555451 is a wasteful number, since it uses less digits than its factorization.

21136555451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1921505052.

The product of its digits is 90000, while the sum is 38.

The spelling of 21136555451 in words is "twenty-one billion, one hundred thirty-six million, five hundred fifty-five thousand, four hundred fifty-one".