21041993 has 4 divisors (see below), whose sum is σ = 24048000. Its totient is φ = 18035988.

The previous prime is 21041989. The next prime is 21042013. The reversal of 21041993 is 39914012.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 21041993 - 2² = 21041989 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21041983) 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, 1502993 + ... + 1503006.

It is an arithmetic number, because the mean of its divisors is an integer number (6012000).

Almost surely, 2^21041993 is an apocalyptic number.

It is an amenable number.

21041993 is a deficient number, since it is larger than the sum of its proper divisors (3006007).

21041993 is an equidigital number, since it uses as much as digits as its factorization.

21041993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3006006.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 21041993 is about 4587.1552186513. The cubic root of 21041993 is about 276.0761928198.

The spelling of 21041993 in words is "twenty-one million, forty-one thousand, nine hundred ninety-three".