21057433 has 2 divisors, whose sum is σ = 21057434. Its totient is φ = 21057432.

The previous prime is 21057431. The next prime is 21057467. The reversal of 21057433 is 33475012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14462809 + 6594624 = 3803^2 + 2568^2 .

It is a cyclic number.

It is not a de Polignac number, because 21057433 - 2¹ = 21057431 is a prime.

Together with 21057431, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21057398 and 21057407.

It is not a weakly prime, because it can be changed into another prime (21057431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10528716 + 10528717.

It is an arithmetic number, because the mean of its divisors is an integer number (10528717).

Almost surely, 2^21057433 is an apocalyptic number.

It is an amenable number.

21057433 is a deficient number, since it is larger than the sum of its proper divisors (1).

21057433 is an equidigital number, since it uses as much as digits as its factorization.

21057433 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 21057433 is about 4588.8378703110. The cubic root of 21057433 is about 276.1437018599.

The spelling of 21057433 in words is "twenty-one million, fifty-seven thousand, four hundred thirty-three".