21251949 has 8 divisors (see below), whose sum is σ = 29101920. Its totient is φ = 13784976.

The previous prime is 21251941. The next prime is 21251987. The reversal of 21251949 is 94915212.

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

It is not a de Polignac number, because 21251949 - 2³ = 21251941 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251941) 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, 95619 + ... + 95840.

It is an arithmetic number, because the mean of its divisors is an integer number (3637740).

Almost surely, 2^21251949 is an apocalyptic number.

It is an amenable number.

21251949 is a deficient number, since it is larger than the sum of its proper divisors (7849971).

21251949 is a wasteful number, since it uses less digits than its factorization.

21251949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191499.

The product of its digits is 6480, while the sum is 33.

The square root of 21251949 is about 4609.9836225306. The cubic root of 21251949 is about 276.9913806525.

The spelling of 21251949 in words is "twenty-one million, two hundred fifty-one thousand, nine hundred forty-nine".