21643093 has 4 divisors (see below), whose sum is σ = 21673120. Its totient is φ = 21613068.

The previous prime is 21643087. The next prime is 21643099. The reversal of 21643093 is 39034612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21643087) and next prime (21643099).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21643093 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 (21643099) 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, 13905 + ... + 15382.

It is an arithmetic number, because the mean of its divisors is an integer number (5418280).

Almost surely, 2^21643093 is an apocalyptic number.

It is an amenable number.

21643093 is a deficient number, since it is larger than the sum of its proper divisors (30027).

21643093 is an equidigital number, since it uses as much as digits as its factorization.

21643093 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30026.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 21643093 is about 4652.2137741080. The cubic root of 21643093 is about 278.6804106820.

The spelling of 21643093 in words is "twenty-one million, six hundred forty-three thousand, ninety-three".