21618470 has 16 divisors (see below), whose sum is σ = 40169088. Its totient is φ = 8368320.

The previous prime is 21618451. The next prime is 21618479. The reversal of 21618470 is 7481612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21618479) 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, 34559 + ... + 35178.

It is an arithmetic number, because the mean of its divisors is an integer number (2510568).

Almost surely, 2^21618470 is an apocalyptic number.

21618470 is a deficient number, since it is larger than the sum of its proper divisors (18550618).

21618470 is a wasteful number, since it uses less digits than its factorization.

21618470 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69775.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 21618470 is about 4649.5666464736. The cubic root of 21618470 is about 278.5746871664.

The spelling of 21618470 in words is "twenty-one million, six hundred eighteen thousand, four hundred seventy".