21931149 has 8 divisors (see below), whose sum is σ = 30780640. Its totient is φ = 13851216.

The previous prime is 21931141. The next prime is 21931157. The reversal of 21931149 is 94113912.

It is an interprime number because it is at equal distance from previous prime (21931141) and next prime (21931157).

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

It is not a de Polignac number, because 21931149 - 2³ = 21931141 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 (21931141) 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, 192322 + ... + 192435.

It is an arithmetic number, because the mean of its divisors is an integer number (3847580).

Almost surely, 2^21931149 is an apocalyptic number.

It is an amenable number.

21931149 is a deficient number, since it is larger than the sum of its proper divisors (8849491).

21931149 is a wasteful number, since it uses less digits than its factorization.

21931149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384779.

The product of its digits is 1944, while the sum is 30.

The square root of 21931149 is about 4683.0704671188. The cubic root of 21931149 is about 279.9113197057.

The spelling of 21931149 in words is "twenty-one million, nine hundred thirty-one thousand, one hundred forty-nine".