861945639 has 8 divisors (see below), whose sum is σ = 1149431040. Its totient is φ = 574545336.

The previous prime is 861945619. The next prime is 861945647. The reversal of 861945639 is 936549168.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 861945639 - 2²¹ = 859848487 is a prime.

It is a super-2 number, since 2×861945639² = 1485900569182236642, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 861945591 and 861945600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861945619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8194 + ... + 42320.

It is an arithmetic number, because the mean of its divisors is an integer number (143678880).

Almost surely, 2^861945639 is an apocalyptic number.

861945639 is a deficient number, since it is larger than the sum of its proper divisors (287485401).

861945639 is a wasteful number, since it uses less digits than its factorization.

861945639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42549.

The product of its digits is 1399680, while the sum is 51.

The square root of 861945639 is about 29358.9107257064. The cubic root of 861945639 is about 951.6851490275.

The spelling of 861945639 in words is "eight hundred sixty-one million, nine hundred forty-five thousand, six hundred thirty-nine".