309213840 has 320 divisors, whose sum is σ = 1119928320. Its totient is φ = 69949440.

The previous prime is 309213829. The next prime is 309213881. The reversal of 309213840 is 48312903.

It is a super-2 number, since 2×309213840² = 191226397695091200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 309213798 and 309213807.

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 63 ways as a sum of consecutive naturals, for example, 2224491 + ... + 2224629.

It is an arithmetic number, because the mean of its divisors is an integer number (3499776).

Almost surely, 2^309213840 is an apocalyptic number.

309213840 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 309213840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (559964160).

309213840 is an abundant number, since it is smaller than the sum of its proper divisors (810714480).

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

309213840 is a wasteful number, since it uses less digits than its factorization.

309213840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222 (or 216 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 309213840 is about 17584.4772455709. The cubic root of 309213840 is about 676.2173478015.

The spelling of 309213840 in words is "three hundred nine million, two hundred thirteen thousand, eight hundred forty".