861131601 has 16 divisors (see below), whose sum is σ = 1391728320. Its totient is φ = 521897760.

The previous prime is 861131581. The next prime is 861131611. The reversal of 861131601 is 106131168.

It is not a de Polignac number, because 861131601 - 2¹⁰ = 861130577 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (861131611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1449420 + ... + 1450013.

It is an arithmetic number, because the mean of its divisors is an integer number (86983020).

Almost surely, 2^861131601 is an apocalyptic number.

It is an amenable number.

861131601 is a deficient number, since it is larger than the sum of its proper divisors (530596719).

861131601 is a wasteful number, since it uses less digits than its factorization.

861131601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2899453 (or 2899447 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 861131601 is about 29345.0438916012. The cubic root of 861131601 is about 951.3854580914.

Adding to 861131601 its reverse (106131168), we get a palindrome (967262769).

The spelling of 861131601 in words is "eight hundred sixty-one million, one hundred thirty-one thousand, six hundred one".