20821153 has 8 divisors (see below), whose sum is σ = 21391776. Its totient is φ = 20253600.

The previous prime is 20821117. The next prime is 20821193. The reversal of 20821153 is 35112802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20821153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20821193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20958 + ... + 21928.

It is an arithmetic number, because the mean of its divisors is an integer number (2673972).

Almost surely, 2^20821153 is an apocalyptic number.

It is an amenable number.

20821153 is a deficient number, since it is larger than the sum of its proper divisors (570623).

20821153 is an equidigital number, since it uses as much as digits as its factorization.

20821153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1535.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 20821153 is about 4563.0201621295. The cubic root of 20821153 is about 275.1069688544.

Adding to 20821153 its reverse (35112802), we get a palindrome (55933955).

It can be divided in two parts, 2082115 and 3, that multiplied together give a triangular number (6246345 = T₃₅₃₄).

The spelling of 20821153 in words is "twenty million, eight hundred twenty-one thousand, one hundred fifty-three".