21955499 has 8 divisors (see below), whose sum is σ = 22722480. Its totient is φ = 21200256.

The previous prime is 21955463. The next prime is 21955559. The reversal of 21955499 is 99455912.

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 21955499 - 2¹⁶ = 21889963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21955429) 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, 959 + ... + 6695.

It is an arithmetic number, because the mean of its divisors is an integer number (2840310).

Almost surely, 2^21955499 is an apocalyptic number.

21955499 is a deficient number, since it is larger than the sum of its proper divisors (766981).

21955499 is an equidigital number, since it uses as much as digits as its factorization.

21955499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5869.

The product of its digits is 145800, while the sum is 44.

The square root of 21955499 is about 4685.6695359361. The cubic root of 21955499 is about 280.0148759103.

The spelling of 21955499 in words is "twenty-one million, nine hundred fifty-five thousand, four hundred ninety-nine".