20700561 has 8 divisors (see below), whose sum is σ = 31543744. Its totient is φ = 11828880.

The previous prime is 20700553. The next prime is 20700593. The reversal of 20700561 is 16500702.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20700561 - 2³ = 20700553 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 985741 = 20700561 / (2 + 0 + 7 + 0 + 0 + 5 + 6 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20700551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 492850 + ... + 492891.

It is an arithmetic number, because the mean of its divisors is an integer number (3942968).

Almost surely, 2^20700561 is an apocalyptic number.

20700561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20700561 is a deficient number, since it is larger than the sum of its proper divisors (10843183).

20700561 is an equidigital number, since it uses as much as digits as its factorization.

20700561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 985751.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 20700561 is about 4549.7869180875. The cubic root of 20700561 is about 274.5748184414.

The spelling of 20700561 in words is "twenty million, seven hundred thousand, five hundred sixty-one".