2871780921 has 9 divisors (see below), whose sum is σ = 4148360229. Its totient is φ = 1914413436.

The previous prime is 2871780869. The next prime is 2871780979. The reversal of 2871780921 is 1290871782.

The square root of 2871780921 is 53589.

It is a perfect power (a square), and thus also a powerful number.

It is a tau number, because it is divible by the number of its divisors (9).

It is a de Polignac number, because none of the positive numbers 2^k-2871780921 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2871780421) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 151836 + ... + 169698.

Almost surely, 2^2871780921 is an apocalyptic number.

2871780921 is the 53589-th square number.

2871780921 is the 26795-th centered octagonal number.

It is an amenable number.

2871780921 is a deficient number, since it is larger than the sum of its proper divisors (1276579308).

2871780921 is an frugal number, since it uses more digits than its factorization.

2871780921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35732 (or 17866 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 45.

The cubic root of 2871780921 is about 1421.4025883981.

Multiplying 2871780921 by its product of nonzero digits (112896), we get a square (324212578857216 = 18005904²).

The spelling of 2871780921 in words is "two billion, eight hundred seventy-one million, seven hundred eighty thousand, nine hundred twenty-one".