21799651 has 4 divisors (see below), whose sum is σ = 21818512. Its totient is φ = 21780792.

The previous prime is 21799649. The next prime is 21799691. The reversal of 21799651 is 15699712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21799651 - 2¹ = 21799649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21799691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7575 + ... + 10048.

It is an arithmetic number, because the mean of its divisors is an integer number (5454628).

Almost surely, 2^21799651 is an apocalyptic number.

21799651 is a deficient number, since it is larger than the sum of its proper divisors (18861).

21799651 is a wasteful number, since it uses less digits than its factorization.

21799651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18860.

The product of its digits is 34020, while the sum is 40.

The square root of 21799651 is about 4669.0096380282. The cubic root of 21799651 is about 279.3507533839.

The spelling of 21799651 in words is "twenty-one million, seven hundred ninety-nine thousand, six hundred fifty-one".