20364561 has 64 divisors (see below), whose sum is σ = 37324800. Its totient is φ = 10715328.

The previous prime is 20364559. The next prime is 20364563. The reversal of 20364561 is 16546302.

20364561 is a `hidden beast` number, since 203 + 6 + 456 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (20364559) and next prime (20364563).

It is not a de Polignac number, because 20364561 - 2¹ = 20364559 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (20364563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 190270 + ... + 190376.

It is an arithmetic number, because the mean of its divisors is an integer number (583200).

Almost surely, 2^20364561 is an apocalyptic number.

20364561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20364561 is a deficient number, since it is larger than the sum of its proper divisors (16960239).

20364561 is a wasteful number, since it uses less digits than its factorization.

20364561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 20364561 is about 4512.7110476963. The cubic root of 20364561 is about 273.0811255097.

The spelling of 20364561 in words is "twenty million, three hundred sixty-four thousand, five hundred sixty-one".