21413993 has 2 divisors, whose sum is σ = 21413994. Its totient is φ = 21413992.

The previous prime is 21413971. The next prime is 21414037. The reversal of 21413993 is 39931412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12581209 + 8832784 = 3547^2 + 2972^2 .

It is a cyclic number.

It is not a de Polignac number, because 21413993 - 2⁸ = 21413737 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21413393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10706996 + 10706997.

It is an arithmetic number, because the mean of its divisors is an integer number (10706997).

Almost surely, 2^21413993 is an apocalyptic number.

It is an amenable number.

21413993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21413993 is an equidigital number, since it uses as much as digits as its factorization.

21413993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 32.

The square root of 21413993 is about 4627.5255806964. The cubic root of 21413993 is about 277.6936094443.

The spelling of 21413993 in words is "twenty-one million, four hundred thirteen thousand, nine hundred ninety-three".