28947209081 has 6 divisors (see below), whose sum is σ = 33673284090. Its totient is φ = 24811893456.

The previous prime is 28947209069. The next prime is 28947209113. The reversal of 28947209081 is 18090274982.

It can be written as a sum of positive squares in only one way, i.e., 18910375225 + 10036833856 = 137515^2 + 100184^2 .

It is not a de Polignac number, because 28947209081 - 2¹⁰ = 28947208057 is a prime.

It is a super-2 number, since 2×28947209081² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28947209581) 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, 295379636 + ... + 295379733.

It is an arithmetic number, because the mean of its divisors is an integer number (5612214015).

Almost surely, 2^28947209081 is an apocalyptic number.

It is an amenable number.

28947209081 is a deficient number, since it is larger than the sum of its proper divisors (4726075009).

28947209081 is an equidigital number, since it uses as much as digits as its factorization.

28947209081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 590759383 (or 590759376 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 50.

The spelling of 28947209081 in words is "twenty-eight billion, nine hundred forty-seven million, two hundred nine thousand, eighty-one".