21311963 has 8 divisors (see below), whose sum is σ = 22217232. Its totient is φ = 20424096.

The previous prime is 21311959. The next prime is 21311981. The reversal of 21311963 is 36911312.

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

It is a cyclic number.

It is not a de Polignac number, because 21311963 - 2² = 21311959 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21311903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1820 + ... + 6777.

It is an arithmetic number, because the mean of its divisors is an integer number (2777154).

Almost surely, 2^21311963 is an apocalyptic number.

21311963 is a deficient number, since it is larger than the sum of its proper divisors (905269).

21311963 is an equidigital number, since it uses as much as digits as its factorization.

21311963 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8701.

The product of its digits is 972, while the sum is 26.

The square root of 21311963 is about 4616.4881674277. The cubic root of 21311963 is about 277.2518702903.

The spelling of 21311963 in words is "twenty-one million, three hundred eleven thousand, nine hundred sixty-three".