20515716 has 72 divisors (see below), whose sum is σ = 56871360. Its totient is φ = 6197184.

The previous prime is 20515709. The next prime is 20515739. The reversal of 20515716 is 61751502.

It is a self number, because there is not a number n which added to its sum of digits gives 20515716.

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, 27241 + ... + 27983.

It is an arithmetic number, because the mean of its divisors is an integer number (789880).

Almost surely, 2^20515716 is an apocalyptic number.

20515716 is a gapful number since it is divisible by the number (26) 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 20515716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28435680).

20515716 is an abundant number, since it is smaller than the sum of its proper divisors (36355644).

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

20515716 is a wasteful number, since it uses less digits than its factorization.

20515716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 825 (or 820 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The square root of 20515716 is about 4529.4277784285. The cubic root of 20515716 is about 273.7551046774.

The spelling of 20515716 in words is "twenty million, five hundred fifteen thousand, seven hundred sixteen".