138721510 has 32 divisors (see below), whose sum is σ = 267613632. Its totient is φ = 51638400.

The previous prime is 138721493. The next prime is 138721519. The reversal of 138721510 is 15127831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138721519) 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, 360 + ... + 16660.

It is an arithmetic number, because the mean of its divisors is an integer number (8362926).

Almost surely, 2^138721510 is an apocalyptic number.

138721510 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

138721510 is a deficient number, since it is larger than the sum of its proper divisors (128892122).

138721510 is a wasteful number, since it uses less digits than its factorization.

138721510 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16368.

The product of its (nonzero) digits is 1680, while the sum is 28.

The square root of 138721510 is about 11778.0095941547. The cubic root of 138721510 is about 517.6639666507.

The spelling of 138721510 in words is "one hundred thirty-eight million, seven hundred twenty-one thousand, five hundred ten".