861537420 has 72 divisors (see below), whose sum is σ = 2623879440. Its totient is φ = 228816000.

The previous prime is 861537409. The next prime is 861537431. The reversal of 861537420 is 24735168.

861537420 is a `hidden beast` number, since 8 + 615 + 37 + 4 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (861537409) and next prime (861537431).

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35646 + ... + 54714.

It is an arithmetic number, because the mean of its divisors is an integer number (36442770).

Almost surely, 2^861537420 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861537420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1311939720).

861537420 is an abundant number, since it is smaller than the sum of its proper divisors (1762342020).

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

861537420 is a wasteful number, since it uses less digits than its factorization.

861537420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19335 (or 19330 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 861537420 is about 29351.9576859875. The cubic root of 861537420 is about 951.5348853724.

The spelling of 861537420 in words is "eight hundred sixty-one million, five hundred thirty-seven thousand, four hundred twenty".