20121022091 has 4 divisors (see below), whose sum is σ = 20549128992. Its totient is φ = 19692915192.

The previous prime is 20121022079. The next prime is 20121022111. The reversal of 20121022091 is 19022012102.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20121022091 - 2¹⁸ = 20120759947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20121022001) 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, 214053380 + ... + 214053473.

It is an arithmetic number, because the mean of its divisors is an integer number (5137282248).

Almost surely, 2^20121022091 is an apocalyptic number.

20121022091 is a deficient number, since it is larger than the sum of its proper divisors (428106901).

20121022091 is an equidigital number, since it uses as much as digits as its factorization.

20121022091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428106900.

The product of its (nonzero) digits is 144, while the sum is 20.

Adding to 20121022091 its reverse (19022012102), we get a palindrome (39143034193).

The spelling of 20121022091 in words is "twenty billion, one hundred twenty-one million, twenty-two thousand, ninety-one".