21293633 has 2 divisors, whose sum is σ = 21293634. Its totient is φ = 21293632.

The previous prime is 21293599. The next prime is 21293647. The reversal of 21293633 is 33639212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19775809 + 1517824 = 4447^2 + 1232^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21293633 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21293596 and 21293605.

It is not a weakly prime, because it can be changed into another prime (21293663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646816 + 10646817.

It is an arithmetic number, because the mean of its divisors is an integer number (10646817).

Almost surely, 2^21293633 is an apocalyptic number.

It is an amenable number.

21293633 is a deficient number, since it is larger than the sum of its proper divisors (1).

21293633 is an equidigital number, since it uses as much as digits as its factorization.

21293633 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 29.

The square root of 21293633 is about 4614.5024650551. The cubic root of 21293633 is about 277.1723611986.

The spelling of 21293633 in words is "twenty-one million, two hundred ninety-three thousand, six hundred thirty-three".