137721439 has 2 divisors, whose sum is σ = 137721440. Its totient is φ = 137721438.

The previous prime is 137721413. The next prime is 137721457. The reversal of 137721439 is 934127731.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 137721439 - 2²³ = 129332831 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 137721398 and 137721407.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (137721239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68860719 + 68860720.

It is an arithmetic number, because the mean of its divisors is an integer number (68860720).

Almost surely, 2^137721439 is an apocalyptic number.

137721439 is a deficient number, since it is larger than the sum of its proper divisors (1).

137721439 is an equidigital number, since it uses as much as digits as its factorization.

137721439 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31752, while the sum is 37.

The square root of 137721439 is about 11735.4777917220. The cubic root of 137721439 is about 516.4169843653.

The spelling of 137721439 in words is "one hundred thirty-seven million, seven hundred twenty-one thousand, four hundred thirty-nine".