21745746 has 40 divisors (see below), whose sum is σ = 53160624. Its totient is φ = 6589080.

The previous prime is 21745733. The next prime is 21745769. The reversal of 21745746 is 64754712.

It is a self number, because there is not a number n which added to its sum of digits gives 21745746.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4320 + ... + 7883.

Almost surely, 2^21745746 is an apocalyptic number.

21745746 is an abundant number, since it is smaller than the sum of its proper divisors (31414878).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21745746 is a wasteful number, since it uses less digits than its factorization.

21745746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12228 (or 12219 counting only the distinct ones).

The product of its digits is 47040, while the sum is 36.

The square root of 21745746 is about 4663.2334275693. The cubic root of 21745746 is about 279.1203088490.

The spelling of 21745746 in words is "twenty-one million, seven hundred forty-five thousand, seven hundred forty-six".