137721457 has 2 divisors, whose sum is σ = 137721458. Its totient is φ = 137721456.

The previous prime is 137721439. The next prime is 137721491. The reversal of 137721457 is 754127731.

It is a happy number.

137721457 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73977201 + 63744256 = 8601^2 + 7984^2 .

It is a cyclic number.

It is not a de Polignac number, because 137721457 - 2¹⁵ = 137688689 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (137721497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68860728 + 68860729.

It is an arithmetic number, because the mean of its divisors is an integer number (68860729).

Almost surely, 2^137721457 is an apocalyptic number.

It is an amenable number.

137721457 is a deficient number, since it is larger than the sum of its proper divisors (1).

137721457 is an equidigital number, since it uses as much as digits as its factorization.

137721457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41160, while the sum is 37.

The square root of 137721457 is about 11735.4785586273. The cubic root of 137721457 is about 516.4170068636.

The spelling of 137721457 in words is "one hundred thirty-seven million, seven hundred twenty-one thousand, four hundred fifty-seven".