20491560 has 48 divisors (see below), whose sum is σ = 66598740. Its totient is φ = 5464320.

The previous prime is 20491489. The next prime is 20491561. The reversal of 20491560 is 6519402.

It can be written as a sum of positive squares in 2 ways, for example, as 19873764 + 617796 = 4458^2 + 786^2 .

It is not an unprimeable number, because it can be changed into a prime (20491561) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 28101 + ... + 28820.

Almost surely, 2^20491560 is an apocalyptic number.

20491560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20491560 is an abundant number, since it is smaller than the sum of its proper divisors (46107180).

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

20491560 is a wasteful number, since it uses less digits than its factorization.

20491560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56938 (or 56931 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 20491560 is about 4526.7604310367. The cubic root of 20491560 is about 273.6476191867.

The spelling of 20491560 in words is "twenty million, four hundred ninety-one thousand, five hundred sixty".