21203631251 has 8 divisors (see below), whose sum is σ = 23158047744. Its totient is φ = 19253683720.

The previous prime is 21203631223. The next prime is 21203631257. The reversal of 21203631251 is 15213630212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21203631251 - 2⁶ = 21203631187 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 21203631251.

It is not an unprimeable number, because it can be changed into a prime (21203631257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1107311 + ... + 1126296.

It is an arithmetic number, because the mean of its divisors is an integer number (2894755968).

Almost surely, 2^21203631251 is an apocalyptic number.

21203631251 is a deficient number, since it is larger than the sum of its proper divisors (1954416493).

21203631251 is a wasteful number, since it uses less digits than its factorization.

21203631251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2234481.

The product of its (nonzero) digits is 2160, while the sum is 26.

The spelling of 21203631251 in words is "twenty-one billion, two hundred three million, six hundred thirty-one thousand, two hundred fifty-one".