21915755 has 8 divisors (see below), whose sum is σ = 26506752. Its totient is φ = 17394048.

The previous prime is 21915739. The next prime is 21915763. The reversal of 21915755 is 55751912.

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 21915755 - 2⁴ = 21915739 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 16622 + ... + 17891.

It is an arithmetic number, because the mean of its divisors is an integer number (3313344).

Almost surely, 2^21915755 is an apocalyptic number.

21915755 is a deficient number, since it is larger than the sum of its proper divisors (4590997).

21915755 is a wasteful number, since it uses less digits than its factorization.

21915755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34645.

The product of its digits is 15750, while the sum is 35.

The square root of 21915755 is about 4681.4265988051. The cubic root of 21915755 is about 279.8458122177.

The spelling of 21915755 in words is "twenty-one million, nine hundred fifteen thousand, seven hundred fifty-five".