11778572821 has 2 divisors, whose sum is σ = 11778572822. Its totient is φ = 11778572820.

The previous prime is 11778572797. The next prime is 11778572843. The reversal of 11778572821 is 12827587711.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7940770321 + 3837802500 = 89111^2 + 61950^2 .

It is a cyclic number.

It is not a de Polignac number, because 11778572821 - 2⁵ = 11778572789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11778572521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5889286410 + 5889286411.

It is an arithmetic number, because the mean of its divisors is an integer number (5889286411).

Almost surely, 2^11778572821 is an apocalyptic number.

It is an amenable number.

11778572821 is a deficient number, since it is larger than the sum of its proper divisors (1).

11778572821 is an equidigital number, since it uses as much as digits as its factorization.

11778572821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 439040, while the sum is 49.

The spelling of 11778572821 in words is "eleven billion, seven hundred seventy-eight million, five hundred seventy-two thousand, eight hundred twenty-one".