39877434721 has 2 divisors, whose sum is σ = 39877434722. Its totient is φ = 39877434720.

The previous prime is 39877434697. The next prime is 39877434763. The reversal of 39877434721 is 12743477893.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34248684096 + 5628750625 = 185064^2 + 75025^2 .

It is a cyclic number.

It is not a de Polignac number, because 39877434721 - 2¹⁵ = 39877401953 is a prime.

It is not a weakly prime, because it can be changed into another prime (39877434791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19938717360 + 19938717361.

It is an arithmetic number, because the mean of its divisors is an integer number (19938717361).

Almost surely, 2^39877434721 is an apocalyptic number.

It is an amenable number.

39877434721 is a deficient number, since it is larger than the sum of its proper divisors (1).

39877434721 is an equidigital number, since it uses as much as digits as its factorization.

39877434721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7112448, while the sum is 55.

The spelling of 39877434721 in words is "thirty-nine billion, eight hundred seventy-seven million, four hundred thirty-four thousand, seven hundred twenty-one".