20561136 has 40 divisors (see below), whose sum is σ = 53724240. Its totient is φ = 6775296.

The previous prime is 20561117. The next prime is 20561147. The reversal of 20561136 is 63116502.

It is a super-2 number, since 2×20561136² = 845520627220992, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

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, 1866 + ... + 6678.

It is an arithmetic number, because the mean of its divisors is an integer number (1343106).

Almost surely, 2^20561136 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 20561136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26862120).

20561136 is an abundant number, since it is smaller than the sum of its proper divisors (33163104).

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

20561136 is a wasteful number, since it uses less digits than its factorization.

20561136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4913 (or 4907 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 20561136 is about 4534.4388848015. The cubic root of 20561136 is about 273.9569790555.

Adding to 20561136 its reverse (63116502), we get a palindrome (83677638).

The spelling of 20561136 in words is "twenty million, five hundred sixty-one thousand, one hundred thirty-six".