21033497 has 4 divisors (see below), whose sum is σ = 21758820. Its totient is φ = 20308176.

The previous prime is 21033479. The next prime is 21033517. The reversal of 21033497 is 79433012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13075456 + 7958041 = 3616^2 + 2821^2 .

It is a cyclic number.

It is not a de Polignac number, because 21033497 - 2⁶ = 21033433 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 725293 = 21033497 / (2 + 1 + 0 + 3 + 3 + 4 + 9 + 7).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21233497) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 362618 + ... + 362675.

It is an arithmetic number, because the mean of its divisors is an integer number (5439705).

Almost surely, 2^21033497 is an apocalyptic number.

It is an amenable number.

21033497 is a deficient number, since it is larger than the sum of its proper divisors (725323).

21033497 is an equidigital number, since it uses as much as digits as its factorization.

21033497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 725322.

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 21033497 is about 4586.2290610043. The cubic root of 21033497 is about 276.0390312720.

The spelling of 21033497 in words is "twenty-one million, thirty-three thousand, four hundred ninety-seven".