28927090781 has 6 divisors (see below), whose sum is σ = 29925524190. Its totient is φ = 27928720568.

The previous prime is 28927090769. The next prime is 28927090789. The reversal of 28927090781 is 18709072982.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 24937147225 + 3989943556 = 157915^2 + 63166^2 .

It is not a de Polignac number, because 28927090781 - 2²² = 28922896477 is a prime.

It is a super-2 number, since 2×28927090781² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28927090789) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 900116 + ... + 931698.

It is an arithmetic number, because the mean of its divisors is an integer number (4987587365).

Almost surely, 2^28927090781 is an apocalyptic number.

It is an amenable number.

28927090781 is a deficient number, since it is larger than the sum of its proper divisors (998433409).

28927090781 is an frugal number, since it uses more digits than its factorization.

28927090781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63195 (or 31612 counting only the distinct ones).

The product of its (nonzero) digits is 1016064, while the sum is 53.

The spelling of 28927090781 in words is "twenty-eight billion, nine hundred twenty-seven million, ninety thousand, seven hundred eighty-one".