28739861 has 4 divisors (see below), whose sum is σ = 29516652. Its totient is φ = 27963072.

The previous prime is 28739849. The next prime is 28739863. The reversal of 28739861 is 16893782.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11015761 + 17724100 = 3319^2 + 4210^2 .

It is a cyclic number.

It is not a de Polignac number, because 28739861 - 2⁶ = 28739797 is a prime.

It is a super-2 number, since 2×28739861² = 1651959220598642, which 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 (28739863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 388340 + ... + 388413.

It is an arithmetic number, because the mean of its divisors is an integer number (7379163).

Almost surely, 2^28739861 is an apocalyptic number.

It is an amenable number.

28739861 is a deficient number, since it is larger than the sum of its proper divisors (776791).

28739861 is an equidigital number, since it uses as much as digits as its factorization.

28739861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 776790.

The product of its digits is 145152, while the sum is 44.

The square root of 28739861 is about 5360.9570973848. The cubic root of 28739861 is about 306.3102674116.

The spelling of 28739861 in words is "twenty-eight million, seven hundred thirty-nine thousand, eight hundred sixty-one".