21268651 has 4 divisors (see below), whose sum is σ = 21306600. Its totient is φ = 21230704.

The previous prime is 21268631. The next prime is 21268661. The reversal of 21268651 is 15686212.

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 21268651 - 2¹¹ = 21266603 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (21268631) 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, 18121 + ... + 19258.

It is an arithmetic number, because the mean of its divisors is an integer number (5326650).

Almost surely, 2^21268651 is an apocalyptic number.

21268651 is a deficient number, since it is larger than the sum of its proper divisors (37949).

21268651 is an equidigital number, since it uses as much as digits as its factorization.

21268651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37948.

The product of its digits is 5760, while the sum is 31.

The square root of 21268651 is about 4611.7947699350. The cubic root of 21268651 is about 277.0639245656.

The spelling of 21268651 in words is "twenty-one million, two hundred sixty-eight thousand, six hundred fifty-one".