309430638 has 192 divisors, whose sum is σ = 827366400. Its totient is φ = 85377600.

The previous prime is 309430631. The next prime is 309430663. The reversal of 309430638 is 836034903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (309430631) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4358143 + ... + 4358213.

It is an arithmetic number, because the mean of its divisors is an integer number (4309200).

Almost surely, 2^309430638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 309430638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (413683200).

309430638 is an abundant number, since it is smaller than the sum of its proper divisors (517935762).

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

309430638 is a wasteful number, since it uses less digits than its factorization.

309430638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 139 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 36.

The square root of 309430638 is about 17590.6406364294. The cubic root of 309430638 is about 676.3753488358.

The spelling of 309430638 in words is "three hundred nine million, four hundred thirty thousand, six hundred thirty-eight".