137651621 has 2 divisors, whose sum is σ = 137651622. Its totient is φ = 137651620.

The previous prime is 137651611. The next prime is 137651627. The reversal of 137651621 is 126156731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137147521 + 504100 = 11711^2 + 710^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-137651621 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (137651627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68825810 + 68825811.

It is an arithmetic number, because the mean of its divisors is an integer number (68825811).

Almost surely, 2^137651621 is an apocalyptic number.

It is an amenable number.

137651621 is a deficient number, since it is larger than the sum of its proper divisors (1).

137651621 is an equidigital number, since it uses as much as digits as its factorization.

137651621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7560, while the sum is 32.

The square root of 137651621 is about 11732.5027594286. The cubic root of 137651621 is about 516.3297036056.

The spelling of 137651621 in words is "one hundred thirty-seven million, six hundred fifty-one thousand, six hundred twenty-one".