21012599 has 2 divisors, whose sum is σ = 21012600. Its totient is φ = 21012598.

The previous prime is 21012583. The next prime is 21012647. The reversal of 21012599 is 99521012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21012599 - 2⁴ = 21012583 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506299 + 10506300.

It is an arithmetic number, because the mean of its divisors is an integer number (10506300).

Almost surely, 2^21012599 is an apocalyptic number.

21012599 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012599 is an equidigital number, since it uses as much as digits as its factorization.

21012599 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 21012599 is about 4583.9501524340. The cubic root of 21012599 is about 275.9475807121.

The spelling of 21012599 in words is "twenty-one million, twelve thousand, five hundred ninety-nine".