139437433721 has 4 divisors (see below), whose sum is σ = 140501841744. Its totient is φ = 138373025700.

The previous prime is 139437433717. The next prime is 139437433769. The reversal of 139437433721 is 127334734931.

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, and also an emirpimes, since its reverse is a distinct semiprime: 127334734931 = 61 ⋅2087454671.

It is a cyclic number.

It is not a de Polignac number, because 139437433721 - 2² = 139437433717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (139437433321) 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, 532203815 + ... + 532204076.

It is an arithmetic number, because the mean of its divisors is an integer number (35125460436).

Almost surely, 2^139437433721 is an apocalyptic number.

It is an amenable number.

139437433721 is a deficient number, since it is larger than the sum of its proper divisors (1064408023).

139437433721 is a wasteful number, since it uses less digits than its factorization.

139437433721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1064408022.

The product of its digits is 1143072, while the sum is 47.

The spelling of 139437433721 in words is "one hundred thirty-nine billion, four hundred thirty-seven million, four hundred thirty-three thousand, seven hundred twenty-one".