21385970 has 32 divisors (see below), whose sum is σ = 40089600. Its totient is φ = 8205120.

The previous prime is 21385967. The next prime is 21385999. The reversal of 21385970 is 7958312.

It is a self number, because there is not a number n which added to its sum of digits gives 21385970.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45959 + ... + 46421.

It is an arithmetic number, because the mean of its divisors is an integer number (1252800).

Almost surely, 2^21385970 is an apocalyptic number.

21385970 is a deficient number, since it is larger than the sum of its proper divisors (18703630).

21385970 is a wasteful number, since it uses less digits than its factorization.

21385970 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 650.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 21385970 is about 4624.4967293750. The cubic root of 21385970 is about 277.5724238097.

The spelling of 21385970 in words is "twenty-one million, three hundred eighty-five thousand, nine hundred seventy".