139187621 has 4 divisors (see below), whose sum is σ = 139916544. Its totient is φ = 138458700.

The previous prime is 139187611. The next prime is 139187623. The reversal of 139187621 is 126781931.

139187621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 139187621 - 2²² = 134993317 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 (139187623) 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, 364175 + ... + 364556.

It is an arithmetic number, because the mean of its divisors is an integer number (34979136).

Almost surely, 2^139187621 is an apocalyptic number.

It is an amenable number.

139187621 is a deficient number, since it is larger than the sum of its proper divisors (728923).

139187621 is an equidigital number, since it uses as much as digits as its factorization.

139187621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 728922.

The product of its digits is 18144, while the sum is 38.

The square root of 139187621 is about 11797.7803420813. The cubic root of 139187621 is about 518.2431104933.

The spelling of 139187621 in words is "one hundred thirty-nine million, one hundred eighty-seven thousand, six hundred twenty-one".