21156344351 has 16 divisors (see below), whose sum is σ = 22205104128. Its totient is φ = 20132011200.

The previous prime is 21156344347. The next prime is 21156344369. The reversal of 21156344351 is 15344365112.

It is a cyclic number.

It is not a de Polignac number, because 21156344351 - 2² = 21156344347 is a prime.

It is a super-2 number, since 2×21156344351² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21156344381) 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, 830435 + ... + 855531.

It is an arithmetic number, because the mean of its divisors is an integer number (1387819008).

Almost surely, 2^21156344351 is an apocalyptic number.

21156344351 is a deficient number, since it is larger than the sum of its proper divisors (1048759777).

21156344351 is a wasteful number, since it uses less digits than its factorization.

21156344351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25582.

The product of its digits is 43200, while the sum is 35.

The spelling of 21156344351 in words is "twenty-one billion, one hundred fifty-six million, three hundred forty-four thousand, three hundred fifty-one".