509164721 has 6 divisors (see below), whose sum is σ = 551344230. Its totient is φ = 469998048.

The previous prime is 509164709. The next prime is 509164727. The reversal of 509164721 is 127461905.

It can be written as a sum of positive squares in 3 ways, for example, as 30625 + 509134096 = 175^2 + 22564^2 .

It is not a de Polignac number, because 509164721 - 2⁶ = 509164657 is a prime.

It is a super-2 number, since 2×509164721² = 518497426222015682, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (509164727) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1506236 + ... + 1506573.

It is an arithmetic number, because the mean of its divisors is an integer number (91890705).

Almost surely, 2^509164721 is an apocalyptic number.

It is an amenable number.

509164721 is a deficient number, since it is larger than the sum of its proper divisors (42179509).

509164721 is a wasteful number, since it uses less digits than its factorization.

509164721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3012835 (or 3012822 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 509164721 is about 22564.6786150390. The cubic root of 509164721 is about 798.5205579380.

The spelling of 509164721 in words is "five hundred nine million, one hundred sixty-four thousand, seven hundred twenty-one".