309490 has 8 divisors (see below), whose sum is σ = 557100. Its totient is φ = 123792.

The previous prime is 309481. The next prime is 309493. The reversal of 309490 is 94903.

It can be written as a sum of positive squares in 2 ways, for example, as 294849 + 14641 = 543^2 + 121^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (309493) by changing a digit.

309490 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15465 + ... + 15484.

2³⁰⁹⁴⁹⁰ is an apocalyptic number.

309490 is a deficient number, since it is larger than the sum of its proper divisors (247610).

309490 is a wasteful number, since it uses less digits than its factorization.

309490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30956.

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 309490 is about 556.3182542394. The cubic root of 309490 is about 67.6418598621.

The spelling of 309490 in words is "three hundred nine thousand, four hundred ninety".