20815164 has 48 divisors (see below), whose sum is σ = 55434400. Its totient is φ = 6749568.

The previous prime is 20815159. The next prime is 20815169. The reversal of 20815164 is 46151802.

It is an interprime number because it is at equal distance from previous prime (20815159) and next prime (20815169).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20815169) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1392 + ... + 6600.

Almost surely, 2^20815164 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 20815164, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27717200).

20815164 is an abundant number, since it is smaller than the sum of its proper divisors (34619236).

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

20815164 is a wasteful number, since it uses less digits than its factorization.

20815164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5259 (or 5251 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 20815164 is about 4562.3638609826. The cubic root of 20815164 is about 275.0805890532.

Adding to 20815164 its reverse (46151802), we get a palindrome (66966966).

The spelling of 20815164 in words is "twenty million, eight hundred fifteen thousand, one hundred sixty-four".