21430710 has 256 divisors, whose sum is σ = 74649600. Its totient is φ = 4257792.

The previous prime is 21430697. The next prime is 21430723. The reversal of 21430710 is 1703412.

It is an interprime number because it is at equal distance from previous prime (21430697) and next prime (21430723).

It is a super-2 number, since 2×21430710² = 918550662208200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 738976 + ... + 739004.

It is an arithmetic number, because the mean of its divisors is an integer number (291600).

Almost surely, 2^21430710 is an apocalyptic number.

21430710 is the 3780-th pentagonal number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21430710, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37324800).

21430710 is an abundant number, since it is smaller than the sum of its proper divisors (53218890).

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

21430710 is a wasteful number, since it uses less digits than its factorization.

21430710 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92 (or 86 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21430710 is about 4629.3314852147. The cubic root of 21430710 is about 277.7658518732.

The spelling of 21430710 in words is "twenty-one million, four hundred thirty thousand, seven hundred ten".