21069870 has 16 divisors (see below), whose sum is σ = 50567760. Its totient is φ = 5618624.

The previous prime is 21069857. The next prime is 21069901. The reversal of 21069870 is 7896012.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 351135 + ... + 351194.

It is an arithmetic number, because the mean of its divisors is an integer number (3160485).

Almost surely, 2^21069870 is an apocalyptic number.

21069870 is an abundant number, since it is smaller than the sum of its proper divisors (29497890).

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

21069870 is a wasteful number, since it uses less digits than its factorization.

21069870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 702339.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 21069870 is about 4590.1928064080. The cubic root of 21069870 is about 276.1980567489.

The spelling of 21069870 in words is "twenty-one million, sixty-nine thousand, eight hundred seventy".