137961561 has 4 divisors (see below), whose sum is σ = 183948752. Its totient is φ = 91974372.

The previous prime is 137961559. The next prime is 137961589. The reversal of 137961561 is 165169731.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165169731 = 3 ⋅55056577.

It is not a de Polignac number, because 137961561 - 2¹ = 137961559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (137961541) 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, 22993591 + ... + 22993596.

It is an arithmetic number, because the mean of its divisors is an integer number (45987188).

Almost surely, 2^137961561 is an apocalyptic number.

It is an amenable number.

137961561 is a deficient number, since it is larger than the sum of its proper divisors (45987191).

137961561 is an equidigital number, since it uses as much as digits as its factorization.

137961561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45987190.

The product of its digits is 34020, while the sum is 39.

The square root of 137961561 is about 11745.7039380362. The cubic root of 137961561 is about 516.7169402809.

The spelling of 137961561 in words is "one hundred thirty-seven million, nine hundred sixty-one thousand, five hundred sixty-one".