391996537 has 8 divisors (see below), whose sum is σ = 403049736. Its totient is φ = 380967552.

The previous prime is 391996513. The next prime is 391996559. The reversal of 391996537 is 735699193.

It can be written as a sum of positive squares in 4 ways, for example, as 47114496 + 344882041 = 6864^2 + 18571^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 391996537 - 2¹¹ = 391994489 is a prime.

It is a super-2 number, since 2×391996537² = 307322570039984738, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391996597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29703 + ... + 40819.

It is an arithmetic number, because the mean of its divisors is an integer number (50381217).

Almost surely, 2^391996537 is an apocalyptic number.

391996537 is a gapful number since it is divisible by the number (37) formed by its first and last digit.

It is an amenable number.

391996537 is a deficient number, since it is larger than the sum of its proper divisors (11053199).

391996537 is a wasteful number, since it uses less digits than its factorization.

391996537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12107.

The product of its digits is 1377810, while the sum is 52.

The square root of 391996537 is about 19798.9024190736. The cubic root of 391996537 is about 731.8589868663.

The spelling of 391996537 in words is "three hundred ninety-one million, nine hundred ninety-six thousand, five hundred thirty-seven".