861807690 has 96 divisors (see below), whose sum is σ = 2412970560. Its totient is φ = 212608512.

The previous prime is 861807689. The next prime is 861807733. The reversal of 861807690 is 96708168.

It is a happy number.

It is a super-2 number, since 2×861807690² = 1485424989086272200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 85497 + ... + 95043.

It is an arithmetic number, because the mean of its divisors is an integer number (25135110).

Almost surely, 2^861807690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861807690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1206485280).

861807690 is an abundant number, since it is smaller than the sum of its proper divisors (1551162870).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

861807690 is a wasteful number, since it uses less digits than its factorization.

861807690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9636 (or 9633 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 861807690 is about 29356.5612768253. The cubic root of 861807690 is about 951.6343759033.

The spelling of 861807690 in words is "eight hundred sixty-one million, eight hundred seven thousand, six hundred ninety".