20818533 has 4 divisors (see below), whose sum is σ = 27758048. Its totient is φ = 13879020.

The previous prime is 20818517. The next prime is 20818537. The reversal of 20818533 is 33581802.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20818533 - 2⁴ = 20818517 is a prime.

It is a super-2 number, since 2×20818533² = 866822632544178, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20818533.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20818537) 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, 3469753 + ... + 3469758.

It is an arithmetic number, because the mean of its divisors is an integer number (6939512).

Almost surely, 2^20818533 is an apocalyptic number.

It is an amenable number.

20818533 is a deficient number, since it is larger than the sum of its proper divisors (6939515).

20818533 is an equidigital number, since it uses as much as digits as its factorization.

20818533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6939514.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 20818533 is about 4562.7330625405. The cubic root of 20818533 is about 275.0954291398.

The spelling of 20818533 in words is "twenty million, eight hundred eighteen thousand, five hundred thirty-three".