139640991 has 8 divisors (see below), whose sum is σ = 212786304. Its totient is φ = 79794840.

The previous prime is 139640869. The next prime is 139641001. The reversal of 139640991 is 199046931.

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

It is not a de Polignac number, because 139640991 - 2¹³ = 139632799 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139640491) 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, 3324765 + ... + 3324806.

It is an arithmetic number, because the mean of its divisors is an integer number (26598288).

Almost surely, 2^139640991 is an apocalyptic number.

139640991 is a deficient number, since it is larger than the sum of its proper divisors (73145313).

139640991 is an equidigital number, since it uses as much as digits as its factorization.

139640991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6649581.

The product of its (nonzero) digits is 52488, while the sum is 42.

The square root of 139640991 is about 11816.9789286433. The cubic root of 139640991 is about 518.8051845101.

The spelling of 139640991 in words is "one hundred thirty-nine million, six hundred forty thousand, nine hundred ninety-one".