21304870 has 16 divisors (see below), whose sum is σ = 38631168. Its totient is φ = 8459200.

The previous prime is 21304867. The next prime is 21304873. The reversal of 21304870 is 7840312.

It is an interprime number because it is at equal distance from previous prime (21304867) and next prime (21304873).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304873) 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, 6406 + ... + 9145.

It is an arithmetic number, because the mean of its divisors is an integer number (2414448).

Almost surely, 2^21304870 is an apocalyptic number.

21304870 is a deficient number, since it is larger than the sum of its proper divisors (17326298).

21304870 is a wasteful number, since it uses less digits than its factorization.

21304870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15695.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 21304870 is about 4615.7198788488. The cubic root of 21304870 is about 277.2211087610.

The spelling of 21304870 in words is "twenty-one million, three hundred four thousand, eight hundred seventy".