21984951 has 8 divisors (see below), whose sum is σ = 29493760. Its totient is φ = 14566392.

The previous prime is 21984947. The next prime is 21984967. The reversal of 21984951 is 15948912.

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

It is not a de Polignac number, because 21984951 - 2² = 21984947 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21984751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21991 + ... + 22968.

It is an arithmetic number, because the mean of its divisors is an integer number (3686720).

Almost surely, 2^21984951 is an apocalyptic number.

21984951 is a deficient number, since it is larger than the sum of its proper divisors (7508809).

21984951 is a wasteful number, since it uses less digits than its factorization.

21984951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45125.

The product of its digits is 25920, while the sum is 39.

The square root of 21984951 is about 4688.8112565980. The cubic root of 21984951 is about 280.1400277497.

The spelling of 21984951 in words is "twenty-one million, nine hundred eighty-four thousand, nine hundred fifty-one".