15640420 has 48 divisors (see below), whose sum is σ = 35078400. Its totient is φ = 5840640.

The previous prime is 15640409. The next prime is 15640441. The reversal of 15640420 is 2404651.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 15640391 and 15640400.

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, 29760 + ... + 30280.

It is an arithmetic number, because the mean of its divisors is an integer number (730800).

Almost surely, 2^15640420 is an apocalyptic number.

15640420 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 15640420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17539200).

15640420 is an abundant number, since it is smaller than the sum of its proper divisors (19437980).

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

15640420 is a wasteful number, since it uses less digits than its factorization.

15640420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 628 (or 626 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 15640420 is about 3954.7970870830. The cubic root of 15640420 is about 250.0822129612.

The spelling of 15640420 in words is "fifteen million, six hundred forty thousand, four hundred twenty".