21790641 has 8 divisors (see below), whose sum is σ = 29080000. Its totient is φ = 14514192.

The previous prime is 21790633. The next prime is 21790673. The reversal of 21790641 is 14609712.

It is a happy number.

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

It is not a de Polignac number, because 21790641 - 2³ = 21790633 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21790599 and 21790608.

It is not an unprimeable number, because it can be changed into a prime (21790621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1860 + ... + 6858.

It is an arithmetic number, because the mean of its divisors is an integer number (3635000).

Almost surely, 2^21790641 is an apocalyptic number.

It is an amenable number.

21790641 is a deficient number, since it is larger than the sum of its proper divisors (7289359).

21790641 is a wasteful number, since it uses less digits than its factorization.

21790641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6455.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21790641 is about 4668.0446655961. The cubic root of 21790641 is about 279.3122619859.

The spelling of 21790641 in words is "twenty-one million, seven hundred ninety thousand, six hundred forty-one".