23121891 has 24 divisors (see below), whose sum is σ = 36416016. Its totient is φ = 14051520.

The previous prime is 23121883. The next prime is 23121899. The reversal of 23121891 is 19812132.

It is an interprime number because it is at equal distance from previous prime (23121883) and next prime (23121899).

It is not a de Polignac number, because 23121891 - 2³ = 23121883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (23121899) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8521 + ... + 10901.

It is an arithmetic number, because the mean of its divisors is an integer number (1517334).

Almost surely, 2^23121891 is an apocalyptic number.

23121891 is a deficient number, since it is larger than the sum of its proper divisors (13294125).

23121891 is a wasteful number, since it uses less digits than its factorization.

23121891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2483 (or 2480 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 23121891 is about 4808.5227461248. The cubic root of 23121891 is about 284.8881925233. Note that the first 3 decimals are identical.

It can be divided in two parts, 231 and 21891, that added together give a palindrome (22122).

The spelling of 23121891 in words is "twenty-three million, one hundred twenty-one thousand, eight hundred ninety-one".