20621666 has 16 divisors (see below), whose sum is σ = 33784128. Its totient is φ = 9382800.

The previous prime is 20621609. The next prime is 20621677. The reversal of 20621666 is 66612602.

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, 3740 + ... + 7431.

It is an arithmetic number, because the mean of its divisors is an integer number (2111508).

Almost surely, 2^20621666 is an apocalyptic number.

20621666 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

20621666 is a deficient number, since it is larger than the sum of its proper divisors (13162462).

20621666 is a wasteful number, since it uses less digits than its factorization.

20621666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11257.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 20621666 is about 4541.1084549920. The cubic root of 20621666 is about 274.2255499809.

The spelling of 20621666 in words is "twenty million, six hundred twenty-one thousand, six hundred sixty-six".