20821403 has 2 divisors, whose sum is σ = 20821404. Its totient is φ = 20821402.

The previous prime is 20821387. The next prime is 20821433. The reversal of 20821403 is 30412802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20821403 - 2⁴ = 20821387 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (20821433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10410701 + 10410702.

It is an arithmetic number, because the mean of its divisors is an integer number (10410702).

Almost surely, 2^20821403 is an apocalyptic number.

20821403 is a deficient number, since it is larger than the sum of its proper divisors (1).

20821403 is an equidigital number, since it uses as much as digits as its factorization.

20821403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 20821403 is about 4563.0475561844. The cubic root of 20821403 is about 275.1080699216.

The spelling of 20821403 in words is "twenty million, eight hundred twenty-one thousand, four hundred three".