309640240 has 80 divisors (see below), whose sum is σ = 886068288. Its totient is φ = 97993728.

The previous prime is 309640229. The next prime is 309640259. The reversal of 309640240 is 42046903.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 309640199 and 309640208.

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 15 ways as a sum of consecutive naturals, for example, 13987 + ... + 28546.

Almost surely, 2^309640240 is an apocalyptic number.

It is an amenable number.

309640240 is an abundant number, since it is smaller than the sum of its proper divisors (576428048).

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

309640240 is a wasteful number, since it uses less digits than its factorization.

309640240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42566 (or 42560 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 309640240 is about 17596.5973983609. The cubic root of 309640240 is about 676.5280353185.

The spelling of 309640240 in words is "three hundred nine million, six hundred forty thousand, two hundred forty".