31991999503 has 2 divisors, whose sum is σ = 31991999504. Its totient is φ = 31991999502.

The previous prime is 31991999489. The next prime is 31991999509. The reversal of 31991999503 is 30599919913.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31991999503 - 2⁵ = 31991999471 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31991999509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15995999751 + 15995999752.

It is an arithmetic number, because the mean of its divisors is an integer number (15995999752).

Almost surely, 2^31991999503 is an apocalyptic number.

31991999503 is a deficient number, since it is larger than the sum of its proper divisors (1).

31991999503 is an equidigital number, since it uses as much as digits as its factorization.

31991999503 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2657205, while the sum is 58.

The spelling of 31991999503 in words is "thirty-one billion, nine hundred ninety-one million, nine hundred ninety-nine thousand, five hundred three".