21660434 has 24 divisors (see below), whose sum is σ = 34639920. Its totient is φ = 10154408.

The previous prime is 21660421. The next prime is 21660449. The reversal of 21660434 is 43406612.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 62249 + ... + 62595.

It is an arithmetic number, because the mean of its divisors is an integer number (1443330).

Almost surely, 2^21660434 is an apocalyptic number.

21660434 is a deficient number, since it is larger than the sum of its proper divisors (12979486).

21660434 is a wasteful number, since it uses less digits than its factorization.

21660434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454 (or 431 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 21660434 is about 4654.0771373066. The cubic root of 21660434 is about 278.7548194385.

The spelling of 21660434 in words is "twenty-one million, six hundred sixty thousand, four hundred thirty-four".