31644779389 has 2 divisors, whose sum is σ = 31644779390. Its totient is φ = 31644779388.

The previous prime is 31644779371. The next prime is 31644779431. The reversal of 31644779389 is 98397744613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21773363364 + 9871416025 = 147558^2 + 99355^2 .

It is a cyclic number.

It is not a de Polignac number, because 31644779389 - 2²⁹ = 31107908477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31644779329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15822389694 + 15822389695.

It is an arithmetic number, because the mean of its divisors is an integer number (15822389695).

Almost surely, 2^31644779389 is an apocalyptic number.

It is an amenable number.

31644779389 is a deficient number, since it is larger than the sum of its proper divisors (1).

31644779389 is an equidigital number, since it uses as much as digits as its factorization.

31644779389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27433728, while the sum is 61.

The spelling of 31644779389 in words is "thirty-one billion, six hundred forty-four million, seven hundred seventy-nine thousand, three hundred eighty-nine".