31949742821 has 2 divisors, whose sum is σ = 31949742822. Its totient is φ = 31949742820.

The previous prime is 31949742817. The next prime is 31949742833. The reversal of 31949742821 is 12824794913.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16696257796 + 15253485025 = 129214^2 + 123505^2 .

It is a cyclic number.

It is not a de Polignac number, because 31949742821 - 2² = 31949742817 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31949742821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31949742841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15974871410 + 15974871411.

It is an arithmetic number, because the mean of its divisors is an integer number (15974871411).

Almost surely, 2^31949742821 is an apocalyptic number.

It is an amenable number.

31949742821 is a deficient number, since it is larger than the sum of its proper divisors (1).

31949742821 is an equidigital number, since it uses as much as digits as its factorization.

31949742821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 50.

The spelling of 31949742821 in words is "thirty-one billion, nine hundred forty-nine million, seven hundred forty-two thousand, eight hundred twenty-one".