861772657 has 4 divisors (see below), whose sum is σ = 865126116. Its totient is φ = 858419200.

The previous prime is 861772651. The next prime is 861772697. The reversal of 861772657 is 756277168.

It is a happy number.

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 396766561 + 465006096 = 19919^2 + 21564^2 .

It is a cyclic number.

It is not a de Polignac number, because 861772657 - 2¹⁹ = 861248369 is a prime.

It is a super-2 number, since 2×861772657² = 1485304224705679298, which contains 22 as substring.

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 861772657.

It is not an unprimeable number, because it can be changed into a prime (861772651) 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, 1676344 + ... + 1676857.

It is an arithmetic number, because the mean of its divisors is an integer number (216281529).

Almost surely, 2^861772657 is an apocalyptic number.

It is an amenable number.

861772657 is a deficient number, since it is larger than the sum of its proper divisors (3353459).

861772657 is a wasteful number, since it uses less digits than its factorization.

861772657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3353458.

The product of its digits is 987840, while the sum is 49.

The square root of 861772657 is about 29355.9645898410. The cubic root of 861772657 is about 951.6214808923.

The spelling of 861772657 in words is "eight hundred sixty-one million, seven hundred seventy-two thousand, six hundred fifty-seven".