21925813 has 8 divisors (see below), whose sum is σ = 26985728. Its totient is φ = 17347824.

The previous prime is 21925807. The next prime is 21925837. The reversal of 21925813 is 31852912.

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

It is not a de Polignac number, because 21925813 - 2¹⁷ = 21794741 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21925853) 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, 120381 + ... + 120562.

It is an arithmetic number, because the mean of its divisors is an integer number (3373216).

Almost surely, 2^21925813 is an apocalyptic number.

It is an amenable number.

21925813 is a deficient number, since it is larger than the sum of its proper divisors (5059915).

21925813 is a wasteful number, since it uses less digits than its factorization.

21925813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240963.

The product of its digits is 4320, while the sum is 31.

The square root of 21925813 is about 4682.5007207688. The cubic root of 21925813 is about 279.8886164119. Note that the first 3 decimals are identical.

The spelling of 21925813 in words is "twenty-one million, nine hundred twenty-five thousand, eight hundred thirteen".