31400763721 has 2 divisors, whose sum is σ = 31400763722. Its totient is φ = 31400763720.

The previous prime is 31400763703. The next prime is 31400763761. The reversal of 31400763721 is 12736700413.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30716418121 + 684345600 = 175261^2 + 26160^2 .

It is an emirp because it is prime and its reverse (12736700413) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31400763721 - 2³¹ = 29253280073 is a prime.

It is not a weakly prime, because it can be changed into another prime (31400763761) 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 as a sum of consecutive naturals, namely, 15700381860 + 15700381861.

It is an arithmetic number, because the mean of its divisors is an integer number (15700381861).

Almost surely, 2^31400763721 is an apocalyptic number.

It is an amenable number.

31400763721 is a deficient number, since it is larger than the sum of its proper divisors (1).

31400763721 is an equidigital number, since it uses as much as digits as its factorization.

31400763721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21168, while the sum is 34.

The spelling of 31400763721 in words is "thirty-one billion, four hundred million, seven hundred sixty-three thousand, seven hundred twenty-one".