1372705721 has 2 divisors, whose sum is σ = 1372705722. Its totient is φ = 1372705720.

The previous prime is 1372705717. The next prime is 1372705739. The reversal of 1372705721 is 1275072731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1351591696 + 21114025 = 36764^2 + 4595^2 .

It is a cyclic number.

It is not a de Polignac number, because 1372705721 - 2² = 1372705717 is a prime.

It is a super-2 number, since 2×1372705721² = 3768641992932259682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1372705751) 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, 686352860 + 686352861.

It is an arithmetic number, because the mean of its divisors is an integer number (686352861).

Almost surely, 2^1372705721 is an apocalyptic number.

It is an amenable number.

1372705721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1372705721 is an equidigital number, since it uses as much as digits as its factorization.

1372705721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20580, while the sum is 35.

The square root of 1372705721 is about 37050.0434682606. The cubic root of 1372705721 is about 1111.3712245129.

The spelling of 1372705721 in words is "one billion, three hundred seventy-two million, seven hundred five thousand, seven hundred twenty-one".