21310951 has 4 divisors (see below), whose sum is σ = 22432600. Its totient is φ = 20189304.

The previous prime is 21310937. The next prime is 21310957. The reversal of 21310951 is 15901312.

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 21310951 - 2⁹ = 21310439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 560796 + ... + 560833.

It is an arithmetic number, because the mean of its divisors is an integer number (5608150).

Almost surely, 2^21310951 is an apocalyptic number.

21310951 is a deficient number, since it is larger than the sum of its proper divisors (1121649).

21310951 is a wasteful number, since it uses less digits than its factorization.

21310951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1121648.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 21310951 is about 4616.3785590006. The cubic root of 21310951 is about 277.2474817796.

The spelling of 21310951 in words is "twenty-one million, three hundred ten thousand, nine hundred fifty-one".