137591821 has 2 divisors, whose sum is σ = 137591822. Its totient is φ = 137591820.

The previous prime is 137591809. The next prime is 137591837. The reversal of 137591821 is 128195731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135978921 + 1612900 = 11661^2 + 1270^2 .

It is a cyclic number.

It is not a de Polignac number, because 137591821 - 2⁹ = 137591309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (137598821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68795910 + 68795911.

It is an arithmetic number, because the mean of its divisors is an integer number (68795911).

Almost surely, 2^137591821 is an apocalyptic number.

It is an amenable number.

137591821 is a deficient number, since it is larger than the sum of its proper divisors (1).

137591821 is an equidigital number, since it uses as much as digits as its factorization.

137591821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15120, while the sum is 37.

The square root of 137591821 is about 11729.9540067299. The cubic root of 137591821 is about 516.2549230633.

The spelling of 137591821 in words is "one hundred thirty-seven million, five hundred ninety-one thousand, eight hundred twenty-one".