21890641 has 8 divisors (see below), whose sum is σ = 24045120. Its totient is φ = 19836432.

The previous prime is 21890629. The next prime is 21890647. The reversal of 21890641 is 14609812.

It is a happy number.

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 21890641 - 2⁷ = 21890513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21890647) 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, 24610 + ... + 25483.

It is an arithmetic number, because the mean of its divisors is an integer number (3005640).

Almost surely, 2^21890641 is an apocalyptic number.

It is an amenable number.

21890641 is a deficient number, since it is larger than the sum of its proper divisors (2154479).

21890641 is a wasteful number, since it uses less digits than its factorization.

21890641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50135.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 21890641 is about 4678.7435279143. The cubic root of 21890641 is about 279.7388764540.

The spelling of 21890641 in words is "twenty-one million, eight hundred ninety thousand, six hundred forty-one".