870885661 has 4 divisors (see below), whose sum is σ = 872335324. Its totient is φ = 869436000.

The previous prime is 870885643. The next prime is 870885677. The reversal of 870885661 is 166588078.

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

It can be written as a sum of positive squares in 2 ways, for example, as 394816900 + 476068761 = 19870^2 + 21819^2 .

It is a cyclic number.

It is not a de Polignac number, because 870885661 - 2²⁹ = 334014749 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 (870885601) 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, 723930 + ... + 725131.

It is an arithmetic number, because the mean of its divisors is an integer number (218083831).

Almost surely, 2^870885661 is an apocalyptic number.

It is an amenable number.

870885661 is a deficient number, since it is larger than the sum of its proper divisors (1449663).

870885661 is a wasteful number, since it uses less digits than its factorization.

870885661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1449662.

The product of its (nonzero) digits is 645120, while the sum is 49.

The square root of 870885661 is about 29510.7719485614. The cubic root of 870885661 is about 954.9641027048.

The spelling of 870885661 in words is "eight hundred seventy million, eight hundred eighty-five thousand, six hundred sixty-one".