20481564 has 12 divisors (see below), whose sum is σ = 47790344. Its totient is φ = 6827184.

The previous prime is 20481557. The next prime is 20481577. The reversal of 20481564 is 46518402.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 853387 + ... + 853410.

Almost surely, 2^20481564 is an apocalyptic number.

It is an amenable number.

20481564 is an abundant number, since it is smaller than the sum of its proper divisors (27308780).

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

20481564 is a wasteful number, since it uses less digits than its factorization.

20481564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706804 (or 1706802 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 20481564 is about 4525.6561955146. The cubic root of 20481564 is about 273.6031158805.

Adding to 20481564 its reverse (46518402), we get a palindrome (66999966).

The spelling of 20481564 in words is "twenty million, four hundred eighty-one thousand, five hundred sixty-four".