21351433 has 2 divisors, whose sum is σ = 21351434. Its totient is φ = 21351432.

The previous prime is 21351413. The next prime is 21351457. The reversal of 21351433 is 33415312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21132409 + 219024 = 4597^2 + 468^2 .

It is a cyclic number.

It is not a de Polignac number, because 21351433 - 2⁵ = 21351401 is a prime.

It is not a weakly prime, because it can be changed into another prime (21351413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675716 + 10675717.

It is an arithmetic number, because the mean of its divisors is an integer number (10675717).

Almost surely, 2^21351433 is an apocalyptic number.

It is an amenable number.

21351433 is a deficient number, since it is larger than the sum of its proper divisors (1).

21351433 is an equidigital number, since it uses as much as digits as its factorization.

21351433 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 22.

The square root of 21351433 is about 4620.7610844968. The cubic root of 21351433 is about 277.4229226184.

Adding to 21351433 its reverse (33415312), we get a palindrome (54766745).

The spelling of 21351433 in words is "twenty-one million, three hundred fifty-one thousand, four hundred thirty-three".