21426515551 has 16 divisors (see below), whose sum is σ = 25308067840. Its totient is φ = 17751558240.

The previous prime is 21426515477. The next prime is 21426515597. The reversal of 21426515551 is 15551562412.

It is a cyclic number.

It is not a de Polignac number, because 21426515551 - 2⁹ = 21426515039 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 21426515551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21426515351) 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 15 ways as a sum of consecutive naturals, for example, 120340 + ... + 239446.

It is an arithmetic number, because the mean of its divisors is an integer number (1581754240).

Almost surely, 2^21426515551 is an apocalyptic number.

21426515551 is a deficient number, since it is larger than the sum of its proper divisors (3881552289).

21426515551 is a wasteful number, since it uses less digits than its factorization.

21426515551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119974.

The product of its digits is 60000, while the sum is 37.

The spelling of 21426515551 in words is "twenty-one billion, four hundred twenty-six million, five hundred fifteen thousand, five hundred fifty-one".