21936457 has 8 divisors (see below), whose sum is σ = 22951296. Its totient is φ = 20926752.

The previous prime is 21936419. The next prime is 21936463. The reversal of 21936457 is 75463912.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21936457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21936487) 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, 9468 + ... + 11554.

It is an arithmetic number, because the mean of its divisors is an integer number (2868912).

Almost surely, 2^21936457 is an apocalyptic number.

It is an amenable number.

21936457 is a deficient number, since it is larger than the sum of its proper divisors (1014839).

21936457 is a wasteful number, since it uses less digits than its factorization.

21936457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2567.

The product of its digits is 45360, while the sum is 37.

The square root of 21936457 is about 4683.6371550324. The cubic root of 21936457 is about 279.9339002133.

The spelling of 21936457 in words is "twenty-one million, nine hundred thirty-six thousand, four hundred fifty-seven".