21275691 has 8 divisors (see below), whose sum is σ = 28425360. Its totient is φ = 14154912.

The previous prime is 21275677. The next prime is 21275693. The reversal of 21275691 is 19657212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21275691 - 2⁵ = 21275659 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21275693) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5440 + ... + 8493.

It is an arithmetic number, because the mean of its divisors is an integer number (3553170).

Almost surely, 2^21275691 is an apocalyptic number.

21275691 is a deficient number, since it is larger than the sum of its proper divisors (7149669).

21275691 is a wasteful number, since it uses less digits than its factorization.

21275691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14445.

The product of its digits is 7560, while the sum is 33.

The square root of 21275691 is about 4612.5579671154. The cubic root of 21275691 is about 277.0944909119.

The spelling of 21275691 in words is "twenty-one million, two hundred seventy-five thousand, six hundred ninety-one".