391552609 has 4 divisors (see below), whose sum is σ = 447488704. Its totient is φ = 335616516.

The previous prime is 391552597. The next prime is 391552613. The reversal of 391552609 is 906255193.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 906255193 = 17 ⋅53309129.

It is a cyclic number.

It is not a de Polignac number, because 391552609 - 2²⁷ = 257334881 is a prime.

It is a super-2 number, since 2×391552609² = 306626891229413762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391552649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27968037 + ... + 27968050.

It is an arithmetic number, because the mean of its divisors is an integer number (111872176).

Almost surely, 2^391552609 is an apocalyptic number.

It is an amenable number.

391552609 is a deficient number, since it is larger than the sum of its proper divisors (55936095).

391552609 is an equidigital number, since it uses as much as digits as its factorization.

391552609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55936094.

The product of its (nonzero) digits is 72900, while the sum is 40.

The square root of 391552609 is about 19787.6883187501. The cubic root of 391552609 is about 731.5826107698.

The spelling of 391552609 in words is "three hundred ninety-one million, five hundred fifty-two thousand, six hundred nine".