138240291 has 8 divisors (see below), whose sum is σ = 210651904. Its totient is φ = 78994440.

The previous prime is 138240287. The next prime is 138240293. The reversal of 138240291 is 192042831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 138240291 - 2² = 138240287 is a prime.

It is a super-2 number, since 2×138240291² = 38220756111529362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138240293) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3291415 + ... + 3291456.

It is an arithmetic number, because the mean of its divisors is an integer number (26331488).

Almost surely, 2^138240291 is an apocalyptic number.

138240291 is a deficient number, since it is larger than the sum of its proper divisors (72411613).

138240291 is an equidigital number, since it uses as much as digits as its factorization.

138240291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6582881.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 138240291 is about 11757.5631403790. The cubic root of 138240291 is about 517.0646884202.

The spelling of 138240291 in words is "one hundred thirty-eight million, two hundred forty thousand, two hundred ninety-one".