15861020 has 48 divisors (see below), whose sum is σ = 38297280. Its totient is φ = 5405184.

The previous prime is 15860993. The next prime is 15861031. The reversal of 15861020 is 2016851.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38576 + ... + 38984.

It is an arithmetic number, because the mean of its divisors is an integer number (797860).

Almost surely, 2^15861020 is an apocalyptic number.

15861020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15861020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19148640).

15861020 is an abundant number, since it is smaller than the sum of its proper divisors (22436260).

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

15861020 is a wasteful number, since it uses less digits than its factorization.

15861020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 702 (or 700 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 15861020 is about 3982.5896097891. The cubic root of 15861020 is about 251.2524879501.

Adding to 15861020 its reverse (2016851), we get a palindrome (17877871).

The spelling of 15861020 in words is "fifteen million, eight hundred sixty-one thousand, twenty".