31520406399 has 4 divisors (see below), whose sum is σ = 42027208536. Its totient is φ = 21013604264.

The previous prime is 31520406361. The next prime is 31520406427. The reversal of 31520406399 is 99360402513.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31520406399 - 2¹¹ = 31520404351 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31520406399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31520406329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5253401064 + ... + 5253401069.

It is an arithmetic number, because the mean of its divisors is an integer number (10506802134).

Almost surely, 2^31520406399 is an apocalyptic number.

31520406399 is a deficient number, since it is larger than the sum of its proper divisors (10506802137).

31520406399 is a wasteful number, since it uses less digits than its factorization.

31520406399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10506802136.

The product of its (nonzero) digits is 174960, while the sum is 42.

The spelling of 31520406399 in words is "thirty-one billion, five hundred twenty million, four hundred six thousand, three hundred ninety-nine".