137821905 has 40 divisors (see below), whose sum is σ = 266073192. Its totient is φ = 67848192.

The previous prime is 137821847. The next prime is 137821933. The reversal of 137821905 is 509128731.

It can be written as a sum of positive squares in 4 ways, for example, as 22924944 + 114896961 = 4788^2 + 10719^2 .

It is not a de Polignac number, because 137821905 - 2¹² = 137817809 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 137821905.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 7824 + ... + 18353.

Almost surely, 2^137821905 is an apocalyptic number.

137821905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

137821905 is a deficient number, since it is larger than the sum of its proper divisors (128251287).

137821905 is a wasteful number, since it uses less digits than its factorization.

137821905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26207 (or 26198 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 137821905 is about 11739.7574506461. The cubic root of 137821905 is about 516.5425270027.

The spelling of 137821905 in words is "one hundred thirty-seven million, eight hundred twenty-one thousand, nine hundred five".