21112651 has 4 divisors (see below), whose sum is σ = 24128752. Its totient is φ = 18096552.

The previous prime is 21112639. The next prime is 21112673. The reversal of 21112651 is 15621112.

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 21112651 - 2⁹ = 21112139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21112601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1508040 + ... + 1508053.

It is an arithmetic number, because the mean of its divisors is an integer number (6032188).

Almost surely, 2^21112651 is an apocalyptic number.

21112651 is a deficient number, since it is larger than the sum of its proper divisors (3016101).

21112651 is an equidigital number, since it uses as much as digits as its factorization.

21112651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3016100.

The product of its digits is 120, while the sum is 19.

The square root of 21112651 is about 4594.8504872302. The cubic root of 21112651 is about 276.3848644329.

Adding to 21112651 its reverse (15621112), we get a palindrome (36733763).

The spelling of 21112651 in words is "twenty-one million, one hundred twelve thousand, six hundred fifty-one".