861993040 has 40 divisors (see below), whose sum is σ = 2018788200. Its totient is φ = 342276096.

The previous prime is 861993031. The next prime is 861993043. The reversal of 861993040 is 40399168.

It can be written as a sum of positive squares in 4 ways, for example, as 47004736 + 814988304 = 6856^2 + 28548^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 861992984 and 861993002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861993043) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 28365 + ... + 50284.

It is an arithmetic number, because the mean of its divisors is an integer number (50469705).

Almost surely, 2^861993040 is an apocalyptic number.

861993040 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

861993040 is an abundant number, since it is smaller than the sum of its proper divisors (1156795160).

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

861993040 is a wasteful number, since it uses less digits than its factorization.

861993040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78799 (or 78793 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 861993040 is about 29359.7179822968. The cubic root of 861993040 is about 951.7025940568.

The spelling of 861993040 in words is "eight hundred sixty-one million, nine hundred ninety-three thousand, forty".