15642020 has 48 divisors (see below), whose sum is σ = 34398000. Its totient is φ = 5967360.

The previous prime is 15642013. The next prime is 15642031. The reversal of 15642020 is 2024651.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 5234944 + 10407076 = 2288^2 + 3226^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 15641983 and 15642001.

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, 86330 + ... + 86510.

It is an arithmetic number, because the mean of its divisors is an integer number (716625).

Almost surely, 2^15642020 is an apocalyptic number.

15642020 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 15642020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17199000).

15642020 is an abundant number, since it is smaller than the sum of its proper divisors (18755980).

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

15642020 is a wasteful number, since it uses less digits than its factorization.

15642020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368 (or 366 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 15642020 is about 3954.9993678887. Note that the first 3 decimals coincide. The cubic root of 15642020 is about 250.0907403941.

Adding to 15642020 its reverse (2024651), we get a palindrome (17666671).

The spelling of 15642020 in words is "fifteen million, six hundred forty-two thousand, twenty".