861138017801 has 4 divisors (see below), whose sum is σ = 861396543504. Its totient is φ = 860879492100.

The previous prime is 861138017791. The next prime is 861138017807. The reversal of 861138017801 is 108710831168.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 861138017801 - 2²² = 861133823497 is a prime.

It is a super-4 number, since 4×861138017801⁴ (a number of 49 digits) contains 4444 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861138017807) 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, 129257855 + ... + 129264516.

It is an arithmetic number, because the mean of its divisors is an integer number (215349135876).

Almost surely, 2^861138017801 is an apocalyptic number.

It is an amenable number.

861138017801 is a deficient number, since it is larger than the sum of its proper divisors (258525703).

861138017801 is a wasteful number, since it uses less digits than its factorization.

861138017801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258525702.

The product of its (nonzero) digits is 64512, while the sum is 44.

Adding to 861138017801 its reverse (108710831168), we get a palindrome (969848848969).

The spelling of 861138017801 in words is "eight hundred sixty-one billion, one hundred thirty-eight million, seventeen thousand, eight hundred one".