21627390 has 16 divisors (see below), whose sum is σ = 51905808. Its totient is φ = 5767296.

The previous prime is 21627373. The next prime is 21627401. The reversal of 21627390 is 9372612.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 720913 = 21627390 / (2 + 1 + 6 + 2 + 7 + 3 + 9 + 0).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 360427 + ... + 360486.

It is an arithmetic number, because the mean of its divisors is an integer number (3244113).

Almost surely, 2^21627390 is an apocalyptic number.

21627390 is an abundant number, since it is smaller than the sum of its proper divisors (30278418).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21627390 is a wasteful number, since it uses less digits than its factorization.

21627390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 720923.

The product of its (nonzero) digits is 4536, while the sum is 30.

The square root of 21627390 is about 4650.5257767268. The cubic root of 21627390 is about 278.6129961452.

The spelling of 21627390 in words is "twenty-one million, six hundred twenty-seven thousand, three hundred ninety".