21276691 has 16 divisors (see below), whose sum is σ = 22809600. Its totient is φ = 19813248.

The previous prime is 21276683. The next prime is 21276727. The reversal of 21276691 is 19667212.

It is a cyclic number.

It is not a de Polignac number, because 21276691 - 2³ = 21276683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21276611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 167470 + ... + 167596.

It is an arithmetic number, because the mean of its divisors is an integer number (1425600).

Almost surely, 2^21276691 is an apocalyptic number.

21276691 is a deficient number, since it is larger than the sum of its proper divisors (1532909).

21276691 is a wasteful number, since it uses less digits than its factorization.

21276691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318.

The product of its digits is 9072, while the sum is 34.

The square root of 21276691 is about 4612.6663655634. Note that the first 3 decimals coincide. The cubic root of 21276691 is about 277.0988321756.

The spelling of 21276691 in words is "twenty-one million, two hundred seventy-six thousand, six hundred ninety-one".