21878872801 has 2 divisors, whose sum is σ = 21878872802. Its totient is φ = 21878872800.

The previous prime is 21878872793. The next prime is 21878872817. The reversal of 21878872801 is 10827887812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19336293025 + 2542579776 = 139055^2 + 50424^2 .

It is a cyclic number.

It is not a de Polignac number, because 21878872801 - 2³ = 21878872793 is a prime.

It is not a weakly prime, because it can be changed into another prime (21878812801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10939436400 + 10939436401.

It is an arithmetic number, because the mean of its divisors is an integer number (10939436401).

Almost surely, 2^21878872801 is an apocalyptic number.

It is an amenable number.

21878872801 is a deficient number, since it is larger than the sum of its proper divisors (1).

21878872801 is an equidigital number, since it uses as much as digits as its factorization.

21878872801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 802816, while the sum is 52.

The spelling of 21878872801 in words is "twenty-one billion, eight hundred seventy-eight million, eight hundred seventy-two thousand, eight hundred one".