21901967 has 8 divisors (see below), whose sum is σ = 23265216. Its totient is φ = 20547072.

The previous prime is 21901909. The next prime is 21901969. The reversal of 21901967 is 76910912.

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 21901967 - 2¹⁸ = 21639823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21901969) 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, 3818 + ... + 7640.

It is an arithmetic number, because the mean of its divisors is an integer number (2908152).

Almost surely, 2^21901967 is an apocalyptic number.

21901967 is a deficient number, since it is larger than the sum of its proper divisors (1363249).

21901967 is a wasteful number, since it uses less digits than its factorization.

21901967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4177.

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 21901967 is about 4679.9537390876. The cubic root of 21901967 is about 279.7871128404.

The spelling of 21901967 in words is "twenty-one million, nine hundred one thousand, nine hundred sixty-seven".