21632890 has 8 divisors (see below), whose sum is σ = 38939220. Its totient is φ = 8653152.

The previous prime is 21632879. The next prime is 21632911. The reversal of 21632890 is 9823612.

It can be written as a sum of positive squares in 2 ways, for example, as 21631801 + 1089 = 4651^2 + 33^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1081635 + ... + 1081654.

Almost surely, 2^21632890 is an apocalyptic number.

21632890 is a deficient number, since it is larger than the sum of its proper divisors (17306330).

21632890 is a wasteful number, since it uses less digits than its factorization.

21632890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2163296.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 21632890 is about 4651.1170701241. The cubic root of 21632890 is about 278.6366119028.

It can be divided in two parts, 21632 and 890, that added together give a palindrome (22522).

The spelling of 21632890 in words is "twenty-one million, six hundred thirty-two thousand, eight hundred ninety".