21066610 has 16 divisors (see below), whose sum is σ = 37975896. Its totient is φ = 8414208.

The previous prime is 21066607. The next prime is 21066613. The reversal of 21066610 is 1666012.

It is an interprime number because it is at equal distance from previous prime (21066607) and next prime (21066613).

It can be written as a sum of positive squares in 4 ways, for example, as 13564489 + 7502121 = 3683^2 + 2739^2 .

It is not an unprimeable number, because it can be changed into a prime (21066613) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8914 + ... + 11026.

Almost surely, 2^21066610 is an apocalyptic number.

21066610 is a deficient number, since it is larger than the sum of its proper divisors (16909286).

21066610 is a wasteful number, since it uses less digits than its factorization.

21066610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3117.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21066610 is about 4589.8376877620. The cubic root of 21066610 is about 276.1838112551.

The spelling of 21066610 in words is "twenty-one million, sixty-six thousand, six hundred ten".