21621194 has 32 divisors (see below), whose sum is σ = 38085120. Its totient is φ = 9015552.

The previous prime is 21621181. The next prime is 21621233. The reversal of 21621194 is 49112612.

It is a super-4 number, since 4×21621194⁴ (a number of 30 digits) contains 4444 as substring.

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 15 ways as a sum of consecutive naturals, for example, 124892 + ... + 125064.

It is an arithmetic number, because the mean of its divisors is an integer number (1190160).

Almost surely, 2^21621194 is an apocalyptic number.

21621194 is a deficient number, since it is larger than the sum of its proper divisors (16463926).

21621194 is a wasteful number, since it uses less digits than its factorization.

21621194 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374.

The product of its digits is 864, while the sum is 26.

The square root of 21621194 is about 4649.8595677719. The cubic root of 21621194 is about 278.5863871245.

The spelling of 21621194 in words is "twenty-one million, six hundred twenty-one thousand, one hundred ninety-four".