391542516 has 18 divisors (see below), whose sum is σ = 989732562. Its totient is φ = 130514160.

The previous prime is 391542499. The next prime is 391542517. The reversal of 391542516 is 615245193.

391542516 is a `hidden beast` number, since 3 + 91 + 54 + 2 + 516 = 666.

It can be written as a sum of positive squares in only one way, i.e., 378146916 + 13395600 = 19446^2 + 3660^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×391542516² = 306611083671220512, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 10876181 = 391542516 / (3 + 9 + 1 + 5 + 4 + 2 + 5 + 1 + 6).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391542517) 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, 5438055 + ... + 5438126.

Almost surely, 2^391542516 is an apocalyptic number.

391542516 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

391542516 is an abundant number, since it is smaller than the sum of its proper divisors (598190046).

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

391542516 is a wasteful number, since it uses less digits than its factorization.

391542516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10876191 (or 10876186 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 391542516 is about 19787.4332847896. The cubic root of 391542516 is about 731.5763247462.

The spelling of 391542516 in words is "three hundred ninety-one million, five hundred forty-two thousand, five hundred sixteen".