137699621 has 2 divisors, whose sum is σ = 137699622. Its totient is φ = 137699620.

The previous prime is 137699603. The next prime is 137699633. The reversal of 137699621 is 126996731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120143521 + 17556100 = 10961^2 + 4190^2 .

It is a cyclic number.

It is not a de Polignac number, because 137699621 - 2⁶ = 137699557 is a prime.

It is a super-2 number, since 2×137699621² = 37922371247087282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (137699921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68849810 + 68849811.

It is an arithmetic number, because the mean of its divisors is an integer number (68849811).

Almost surely, 2^137699621 is an apocalyptic number.

It is an amenable number.

137699621 is a deficient number, since it is larger than the sum of its proper divisors (1).

137699621 is an equidigital number, since it uses as much as digits as its factorization.

137699621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 44.

The square root of 137699621 is about 11734.5481804797. The cubic root of 137699621 is about 516.3897124535.

The spelling of 137699621 in words is "one hundred thirty-seven million, six hundred ninety-nine thousand, six hundred twenty-one".