21266961 has 8 divisors (see below), whose sum is σ = 29270784. Its totient is φ = 13720560.

The previous prime is 21266953. The next prime is 21266977. The reversal of 21266961 is 16966212.

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

It is not a de Polignac number, because 21266961 - 2³ = 21266953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21266911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114246 + ... + 114431.

It is an arithmetic number, because the mean of its divisors is an integer number (3658848).

Almost surely, 2^21266961 is an apocalyptic number.

It is an amenable number.

21266961 is a deficient number, since it is larger than the sum of its proper divisors (8003823).

21266961 is a wasteful number, since it uses less digits than its factorization.

21266961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228711.

The product of its digits is 7776, while the sum is 33.

The square root of 21266961 is about 4611.6115404487. The cubic root of 21266961 is about 277.0565859018.

The spelling of 21266961 in words is "twenty-one million, two hundred sixty-six thousand, nine hundred sixty-one".