138861887 has 4 divisors (see below), whose sum is σ = 138926040. Its totient is φ = 138797736.

The previous prime is 138861883. The next prime is 138861907. The reversal of 138861887 is 788168831.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 138861887 - 2² = 138861883 is a prime.

It is a super-2 number, since 2×138861887² = 38565247322401538, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138861881) 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, 28712 + ... + 33197.

It is an arithmetic number, because the mean of its divisors is an integer number (34731510).

Almost surely, 2^138861887 is an apocalyptic number.

138861887 is a deficient number, since it is larger than the sum of its proper divisors (64153).

138861887 is an equidigital number, since it uses as much as digits as its factorization.

138861887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64152.

The product of its digits is 516096, while the sum is 50.

The square root of 138861887 is about 11783.9673709664. The cubic root of 138861887 is about 517.8385216918.

The spelling of 138861887 in words is "one hundred thirty-eight million, eight hundred sixty-one thousand, eight hundred eighty-seven".