28156081 has 4 divisors (see below), whose sum is σ = 29638000. Its totient is φ = 26674164.

The previous prime is 28156067. The next prime is 28156123. The reversal of 28156081 is 18065182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28156081 - 2⁵ = 28156049 is a prime.

It is a super-2 number, since 2×28156081² = 1585529794557122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28156061) 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, 740931 + ... + 740968.

It is an arithmetic number, because the mean of its divisors is an integer number (7409500).

Almost surely, 2^28156081 is an apocalyptic number.

It is an amenable number.

28156081 is a deficient number, since it is larger than the sum of its proper divisors (1481919).

28156081 is a wasteful number, since it uses less digits than its factorization.

28156081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1481918.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 28156081 is about 5306.2303945456. The cubic root of 28156081 is about 304.2220827869. Note that the first 3 decimals are identical.

The spelling of 28156081 in words is "twenty-eight million, one hundred fifty-six thousand, eighty-one".