21263536251 has 12 divisors (see below), whose sum is σ = 30723349800. Its totient is φ = 14171374080.

The previous prime is 21263536247. The next prime is 21263536277. The reversal of 21263536251 is 15263536212.

21263536251 is a `hidden beast` number, since 2 + 1 + 26 + 3 + 5 + 3 + 625 + 1 = 666.

It is not a de Polignac number, because 21263536251 - 2² = 21263536247 is a prime.

It is a super-2 number, since 2×21263536251² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21263536351) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 328390 + ... + 387771.

It is an arithmetic number, because the mean of its divisors is an integer number (2560279150).

Almost surely, 2^21263536251 is an apocalyptic number.

21263536251 is a deficient number, since it is larger than the sum of its proper divisors (9459813549).

21263536251 is a wasteful number, since it uses less digits than its factorization.

21263536251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 719466 (or 719463 counting only the distinct ones).

The product of its digits is 64800, while the sum is 36.

The spelling of 21263536251 in words is "twenty-one billion, two hundred sixty-three million, five hundred thirty-six thousand, two hundred fifty-one".