20720491 has 8 divisors (see below), whose sum is σ = 22708224. Its totient is φ = 18750120.

The previous prime is 20720459. The next prime is 20720519. The reversal of 20720491 is 19402702.

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 20720491 - 2⁵ = 20720459 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20724491) 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, 1771 + ... + 6676.

It is an arithmetic number, because the mean of its divisors is an integer number (2838528).

Almost surely, 2^20720491 is an apocalyptic number.

20720491 is a deficient number, since it is larger than the sum of its proper divisors (1987733).

20720491 is a wasteful number, since it uses less digits than its factorization.

20720491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8681.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 20720491 is about 4551.9766036306. The cubic root of 20720491 is about 274.6629081777.

The spelling of 20720491 in words is "twenty million, seven hundred twenty thousand, four hundred ninety-one".