21801679 has 4 divisors (see below), whose sum is σ = 21882400. Its totient is φ = 21720960.

The previous prime is 21801673. The next prime is 21801719. The reversal of 21801679 is 97610812.

It is a happy number.

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 21801679 - 2¹³ = 21793487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21801673) 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, 39954 + ... + 40495.

It is an arithmetic number, because the mean of its divisors is an integer number (5470600).

Almost surely, 2^21801679 is an apocalyptic number.

21801679 is a deficient number, since it is larger than the sum of its proper divisors (80721).

21801679 is an equidigital number, since it uses as much as digits as its factorization.

21801679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80720.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 21801679 is about 4669.2268096549. The cubic root of 21801679 is about 279.3594156902.

The spelling of 21801679 in words is "twenty-one million, eight hundred one thousand, six hundred seventy-nine".