20291021111 has 4 divisors (see below), whose sum is σ = 20291311272. Its totient is φ = 20290730952.

The previous prime is 20291021083. The next prime is 20291021117. The reversal of 20291021111 is 11112019202.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 11112019202 = 2 ⋅5556009601.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20291021111 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 (20291021117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31265 + ... + 203861.

It is an arithmetic number, because the mean of its divisors is an integer number (5072827818).

Almost surely, 2^20291021111 is an apocalyptic number.

20291021111 is a deficient number, since it is larger than the sum of its proper divisors (290161).

20291021111 is a wasteful number, since it uses less digits than its factorization.

20291021111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290160.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 20291021111 in words is "twenty billion, two hundred ninety-one million, twenty-one thousand, one hundred eleven".