1376297721 has 6 divisors (see below), whose sum is σ = 1987985610. Its totient is φ = 917531808.

The previous prime is 1376297641. The next prime is 1376297723. The reversal of 1376297721 is 1277926731.

1376297721 is a `hidden beast` number, since 13 + 7 + 629 + 7 + 7 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 848906496 + 527391225 = 29136^2 + 22965^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1376297721 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1376297723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 76460976 + ... + 76460993.

It is an arithmetic number, because the mean of its divisors is an integer number (331330935).

Almost surely, 2^1376297721 is an apocalyptic number.

It is an amenable number.

1376297721 is a deficient number, since it is larger than the sum of its proper divisors (611687889).

1376297721 is a wasteful number, since it uses less digits than its factorization.

1376297721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152921975 (or 152921972 counting only the distinct ones).

The product of its digits is 222264, while the sum is 45.

The square root of 1376297721 is about 37098.4867750694. The cubic root of 1376297721 is about 1112.3397662758.

The spelling of 1376297721 in words is "one billion, three hundred seventy-six million, two hundred ninety-seven thousand, seven hundred twenty-one".