21113951 has 8 divisors (see below), whose sum is σ = 21669120. Its totient is φ = 20563288.

The previous prime is 21113941. The next prime is 21113957. The reversal of 21113951 is 15931112.

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 21113951 - 2⁶ = 21113887 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 (21113957) 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, 9680 + ... + 11658.

It is an arithmetic number, because the mean of its divisors is an integer number (2708640).

Almost surely, 2^21113951 is an apocalyptic number.

21113951 is a deficient number, since it is larger than the sum of its proper divisors (555169).

21113951 is a wasteful number, since it uses less digits than its factorization.

21113951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2253.

The product of its digits is 270, while the sum is 23.

The square root of 21113951 is about 4594.9919477623. The cubic root of 21113951 is about 276.3905370656.

The spelling of 21113951 in words is "twenty-one million, one hundred thirteen thousand, nine hundred fifty-one".