137031721 has 2 divisors, whose sum is σ = 137031722. Its totient is φ = 137031720.

The previous prime is 137031707. The next prime is 137031751. The reversal of 137031721 is 127130731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 85766121 + 51265600 = 9261^2 + 7160^2 .

It is a cyclic number.

It is not a de Polignac number, because 137031721 - 2⁷ = 137031593 is a prime.

It is not a weakly prime, because it can be changed into another prime (137031751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68515860 + 68515861.

It is an arithmetic number, because the mean of its divisors is an integer number (68515861).

Almost surely, 2^137031721 is an apocalyptic number.

It is an amenable number.

137031721 is a deficient number, since it is larger than the sum of its proper divisors (1).

137031721 is an equidigital number, since it uses as much as digits as its factorization.

137031721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 882, while the sum is 25.

The square root of 137031721 is about 11706.0548862544. The cubic root of 137031721 is about 515.5534578476.

The spelling of 137031721 in words is "one hundred thirty-seven million, thirty-one thousand, seven hundred twenty-one".