881720639 has 4 divisors (see below), whose sum is σ = 884904024. Its totient is φ = 878537256.

The previous prime is 881720599. The next prime is 881720641. The reversal of 881720639 is 936027188.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-881720639 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 881720639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (881720689) 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, 1591277 + ... + 1591830.

It is an arithmetic number, because the mean of its divisors is an integer number (221226006).

Almost surely, 2^881720639 is an apocalyptic number.

881720639 is a deficient number, since it is larger than the sum of its proper divisors (3183385).

881720639 is a wasteful number, since it uses less digits than its factorization.

881720639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3183384.

The product of its (nonzero) digits is 145152, while the sum is 44.

The square root of 881720639 is about 29693.7811502678. The cubic root of 881720639 is about 958.9081332623.

The spelling of 881720639 in words is "eight hundred eighty-one million, seven hundred twenty thousand, six hundred thirty-nine".