28221408789961 has 2 divisors, whose sum is σ = 28221408789962. Its totient is φ = 28221408789960.

The previous prime is 28221408789953. The next prime is 28221408790009. The reversal of 28221408789961 is 16998780412282.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25266516549561 + 2954892240400 = 5026581^2 + 1718980^2 .

It is a cyclic number.

It is not a de Polignac number, because 28221408789961 - 2³ = 28221408789953 is a prime.

It is not a weakly prime, because it can be changed into another prime (28221408789361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14110704394980 + 14110704394981.

It is an arithmetic number, because the mean of its divisors is an integer number (14110704394981).

Almost surely, 2^{28221408789961} is an apocalyptic number.

It is an amenable number.

28221408789961 is a deficient number, since it is larger than the sum of its proper divisors (1).

28221408789961 is an equidigital number, since it uses as much as digits as its factorization.

28221408789961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55738368, while the sum is 67.

The spelling of 28221408789961 in words is "twenty-eight trillion, two hundred twenty-one billion, four hundred eight million, seven hundred eighty-nine thousand, nine hundred sixty-one".