20291861 has 8 divisors (see below), whose sum is σ = 20632320. Its totient is φ = 19953648.

The previous prime is 20291857. The next prime is 20291879. The reversal of 20291861 is 16819202.

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

It is a cyclic number.

It is not a de Polignac number, because 20291861 - 2² = 20291857 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20294861) 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 7 ways as a sum of consecutive naturals, for example, 31040 + ... + 31686.

It is an arithmetic number, because the mean of its divisors is an integer number (2579040).

Almost surely, 2^20291861 is an apocalyptic number.

It is an amenable number.

20291861 is a deficient number, since it is larger than the sum of its proper divisors (340459).

20291861 is an equidigital number, since it uses as much as digits as its factorization.

20291861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1123.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 20291861 is about 4504.6488209404. The cubic root of 20291861 is about 272.7557781350.

The spelling of 20291861 in words is "twenty million, two hundred ninety-one thousand, eight hundred sixty-one".