20415564 has 120 divisors (see below), whose sum is σ = 59479728. Its totient is φ = 6065280.

The previous prime is 20415529. The next prime is 20415599. The reversal of 20415564 is 46551402.

It is an interprime number because it is at equal distance from previous prime (20415529) and next prime (20415599).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 155779 + ... + 155909.

Almost surely, 2^20415564 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 20415564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29739864).

20415564 is an abundant number, since it is smaller than the sum of its proper divisors (39064164).

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

20415564 is a wasteful number, since it uses less digits than its factorization.

20415564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 186 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 20415564 is about 4518.3585515096. The cubic root of 20415564 is about 273.3089124854.

Adding to 20415564 its reverse (46551402), we get a palindrome (66966966).

The spelling of 20415564 in words is "twenty million, four hundred fifteen thousand, five hundred sixty-four".