861247281 has 4 divisors (see below), whose sum is σ = 1148329712. Its totient is φ = 574164852.

The previous prime is 861247273. The next prime is 861247313. The reversal of 861247281 is 182742168.

It is a happy number.

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 not a de Polignac number, because 861247281 - 2³ = 861247273 is a prime.

It is a super-2 number, since 2×861247281² = 1483493758059785922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (861247201) 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, 143541211 + ... + 143541216.

It is an arithmetic number, because the mean of its divisors is an integer number (287082428).

Almost surely, 2^861247281 is an apocalyptic number.

It is an amenable number.

861247281 is a deficient number, since it is larger than the sum of its proper divisors (287082431).

861247281 is a wasteful number, since it uses less digits than its factorization.

861247281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287082430.

The product of its digits is 43008, while the sum is 39.

The square root of 861247281 is about 29347.0148567107. The cubic root of 861247281 is about 951.4280575972.

The spelling of 861247281 in words is "eight hundred sixty-one million, two hundred forty-seven thousand, two hundred eighty-one".