21936971 has 4 divisors (see below), whose sum is σ = 25070832. Its totient is φ = 18803112.

The previous prime is 21936961. The next prime is 21936973. The reversal of 21936971 is 17963912.

It is a happy number.

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 21936971 - 2⁶ = 21936907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21936973) 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, 1566920 + ... + 1566933.

It is an arithmetic number, because the mean of its divisors is an integer number (6267708).

Almost surely, 2^21936971 is an apocalyptic number.

21936971 is a deficient number, since it is larger than the sum of its proper divisors (3133861).

21936971 is an equidigital number, since it uses as much as digits as its factorization.

21936971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3133860.

The product of its digits is 20412, while the sum is 38.

The square root of 21936971 is about 4683.6920265961. The cubic root of 21936971 is about 279.9360866026.

The spelling of 21936971 in words is "twenty-one million, nine hundred thirty-six thousand, nine hundred seventy-one".