28780666465761 has 32 divisors (see below), whose sum is σ = 48746897760000. Its totient is φ = 16440112252800.

The previous prime is 28780666465751. The next prime is 28780666465787. The reversal of 28780666465761 is 16756466608782.

It is not a de Polignac number, because 28780666465761 - 2⁹ = 28780666465249 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28780666465761.

It is not an unprimeable number, because it can be changed into a prime (28780666465751) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27177540 + ... + 28216661.

It is an arithmetic number, because the mean of its divisors is an integer number (1523340555000).

Almost surely, 2^{28780666465761} is an apocalyptic number.

28780666465761 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28780666465761 is a deficient number, since it is larger than the sum of its proper divisors (19966231294239).

28780666465761 is a wasteful number, since it uses less digits than its factorization.

28780666465761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55396966 (or 55396960 counting only the distinct ones).

The product of its (nonzero) digits is 975421440, while the sum is 72.

The spelling of 28780666465761 in words is "twenty-eight trillion, seven hundred eighty billion, six hundred sixty-six million, four hundred sixty-five thousand, seven hundred sixty-one".