28401768907561 has 27 divisors (see below), whose sum is σ = 33513806935773. Its totient is φ = 23999256532440.

The previous prime is 28401768907553. The next prime is 28401768907591. The reversal of 28401768907561 is 16570986710482.

The square root of 28401768907561 is 5329331.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 28401768907561 - 2³ = 28401768907553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28401768907493 and 28401768907502.

It is not an unprimeable number, because it can be changed into a prime (28401768907591) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2648672146 + ... + 2648682868.

Almost surely, 2^{28401768907561} is an apocalyptic number.

28401768907561 is the 5329331-st square number.

28401768907561 is the 2664666-th centered octagonal number.

It is an amenable number.

28401768907561 is a deficient number, since it is larger than the sum of its proper divisors (5112038028212).

28401768907561 is an frugal number, since it uses more digits than its factorization.

28401768907561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21602 (or 10801 counting only the distinct ones).

The product of its (nonzero) digits is 40642560, while the sum is 64.

The spelling of 28401768907561 in words is "twenty-eight trillion, four hundred one billion, seven hundred sixty-eight million, nine hundred seven thousand, five hundred sixty-one".