138015661 has 16 divisors (see below), whose sum is σ = 163114240. Its totient is φ = 114307200.

The previous prime is 138015659. The next prime is 138015671. The reversal of 138015661 is 166510831.

It is not a de Polignac number, because 138015661 - 2¹ = 138015659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138015671) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37345 + ... + 40873.

It is an arithmetic number, because the mean of its divisors is an integer number (10194640).

Almost surely, 2^138015661 is an apocalyptic number.

It is an amenable number.

138015661 is a deficient number, since it is larger than the sum of its proper divisors (25098579).

138015661 is a wasteful number, since it uses less digits than its factorization.

138015661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3724.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 138015661 is about 11748.0066819865. The cubic root of 138015661 is about 516.7844729401.

The spelling of 138015661 in words is "one hundred thirty-eight million, fifteen thousand, six hundred sixty-one".