861445440 has 84 divisors (see below), whose sum is σ = 2963023284. Its totient is φ = 229718016.

The previous prime is 861445373. The next prime is 861445483. The reversal of 861445440 is 44544168.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 245611584 + 615833856 = 15672^2 + 24816^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 861445395 and 861445404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 146677 + ... + 152436.

Almost surely, 2^861445440 is an apocalyptic number.

861445440 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

861445440 is an abundant number, since it is smaller than the sum of its proper divisors (2101577844).

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

861445440 is a wasteful number, since it uses less digits than its factorization.

861445440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299136 (or 299123 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 36.

The square root of 861445440 is about 29350.3907980797. The cubic root of 861445440 is about 951.5010213785.

The spelling of 861445440 in words is "eight hundred sixty-one million, four hundred forty-five thousand, four hundred forty".