20015616 has 80 divisors (see below), whose sum is σ = 54309024. Its totient is φ = 6549504.

The previous prime is 20015591. The next prime is 20015623. The reversal of 20015616 is 61651002.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 20015592 and 20015601.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 127410 + ... + 127566.

Almost surely, 2^20015616 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 20015616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27154512).

20015616 is an abundant number, since it is smaller than the sum of its proper divisors (34293408).

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

20015616 is an equidigital number, since it uses as much as digits as its factorization.

20015616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 20015616 is about 4473.8815362054. The cubic root of 20015616 is about 271.5123905228.

Adding to 20015616 its reverse (61651002), we get a palindrome (81666618).

The spelling of 20015616 in words is "twenty million, fifteen thousand, six hundred sixteen".