21202978801 has 2 divisors, whose sum is σ = 21202978802. Its totient is φ = 21202978800.

The previous prime is 21202978793. The next prime is 21202978817. The reversal of 21202978801 is 10887920212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20656588176 + 546390625 = 143724^2 + 23375^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202978801 - 2³ = 21202978793 is a prime.

It is not a weakly prime, because it can be changed into another prime (21202978861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601489400 + 10601489401.

It is an arithmetic number, because the mean of its divisors is an integer number (10601489401).

Almost surely, 2^21202978801 is an apocalyptic number.

It is an amenable number.

21202978801 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202978801 is an equidigital number, since it uses as much as digits as its factorization.

21202978801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 40.

The spelling of 21202978801 in words is "twenty-one billion, two hundred two million, nine hundred seventy-eight thousand, eight hundred one".