21439710 has 48 divisors (see below), whose sum is σ = 56057040. Its totient is φ = 5685120.

The previous prime is 21439699. The next prime is 21439721. The reversal of 21439710 is 1793412.

It is an interprime number because it is at equal distance from previous prime (21439699) and next prime (21439721).

It is a super-2 number, since 2×21439710² = 919322329768200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18426 + ... + 19554.

It is an arithmetic number, because the mean of its divisors is an integer number (1167855).

Almost surely, 2^21439710 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21439710, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28028520).

21439710 is an abundant number, since it is smaller than the sum of its proper divisors (34617330).

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

21439710 is a wasteful number, since it uses less digits than its factorization.

21439710 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1353 (or 1350 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21439710 is about 4630.3034457798. The cubic root of 21439710 is about 277.8047297700.

The spelling of 21439710 in words is "twenty-one million, four hundred thirty-nine thousand, seven hundred ten".