21553690 has 16 divisors (see below), whose sum is σ = 38995200. Its totient is φ = 8577360.

The previous prime is 21553643. The next prime is 21553717. The reversal of 21553690 is 9635512.

It is a super-2 number, since 2×21553690² = 929123105232200, which contains 22 as substring.

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, 3426 + ... + 7405.

It is an arithmetic number, because the mean of its divisors is an integer number (2437200).

Almost surely, 2^21553690 is an apocalyptic number.

21553690 is a deficient number, since it is larger than the sum of its proper divisors (17441510).

21553690 is a wasteful number, since it uses less digits than its factorization.

21553690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11037.

The product of its (nonzero) digits is 8100, while the sum is 31.

The square root of 21553690 is about 4642.5951794228. The cubic root of 21553690 is about 278.2961579984.

The spelling of 21553690 in words is "twenty-one million, five hundred fifty-three thousand, six hundred ninety".