20557030991 has 8 divisors (see below), whose sum is σ = 23570279040. Its totient is φ = 17562915288.

The previous prime is 20557030987. The next prime is 20557030993. The reversal of 20557030991 is 19903075502.

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 20557030991 - 2² = 20557030987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20557030993) 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, 4780781 + ... + 4785078.

It is an arithmetic number, because the mean of its divisors is an integer number (2946284880).

Almost surely, 2^20557030991 is an apocalyptic number.

20557030991 is a deficient number, since it is larger than the sum of its proper divisors (3013248049).

20557030991 is an equidigital number, since it uses as much as digits as its factorization.

20557030991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9566173.

The product of its (nonzero) digits is 85050, while the sum is 41.

The spelling of 20557030991 in words is "twenty billion, five hundred fifty-seven million, thirty thousand, nine hundred ninety-one".