137626721 has 4 divisors (see below), whose sum is σ = 142372500. Its totient is φ = 132880944.

The previous prime is 137626711. The next prime is 137626729. The reversal of 137626721 is 127626731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127626731 = 101 ⋅1263631.

It can be written as a sum of positive squares in 2 ways, for example, as 94789696 + 42837025 = 9736^2 + 6545^2 .

It is a cyclic number.

It is not a de Polignac number, because 137626721 - 2²² = 133432417 is a prime.

It is a super-2 number, since 2×137626721² = 37882228666423682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (137626729) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2372846 + ... + 2372903.

It is an arithmetic number, because the mean of its divisors is an integer number (35593125).

Almost surely, 2^137626721 is an apocalyptic number.

It is an amenable number.

137626721 is a deficient number, since it is larger than the sum of its proper divisors (4745779).

137626721 is an equidigital number, since it uses as much as digits as its factorization.

137626721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4745778.

The product of its digits is 21168, while the sum is 35.

The square root of 137626721 is about 11731.4415567738. The cubic root of 137626721 is about 516.2985685202.

The spelling of 137626721 in words is "one hundred thirty-seven million, six hundred twenty-six thousand, seven hundred twenty-one".