21625371 has 6 divisors (see below), whose sum is σ = 31236660. Its totient is φ = 14416908.

The previous prime is 21625367. The next prime is 21625391. The reversal of 21625371 is 17352612.

It is a happy number.

21625371 is a `hidden beast` number, since 2 + 1 + 625 + 37 + 1 = 666.

It is not a de Polignac number, because 21625371 - 2² = 21625367 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21625391) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1201401 + ... + 1201418.

It is an arithmetic number, because the mean of its divisors is an integer number (5206110).

Almost surely, 2^21625371 is an apocalyptic number.

21625371 is a deficient number, since it is larger than the sum of its proper divisors (9611289).

21625371 is a wasteful number, since it uses less digits than its factorization.

21625371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2402825 (or 2402822 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 21625371 is about 4650.3086994306. The cubic root of 21625371 is about 278.6043260106.

Adding to 21625371 its reverse (17352612), we get a palindrome (38977983).

The spelling of 21625371 in words is "twenty-one million, six hundred twenty-five thousand, three hundred seventy-one".