28081642 has 4 divisors (see below), whose sum is σ = 42122466. Its totient is φ = 14040820.

The previous prime is 28081633. The next prime is 28081649. The reversal of 28081642 is 24618082.

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

It can be written as a sum of positive squares in only one way, i.e., 22648081 + 5433561 = 4759^2 + 2331^2 .

It is not an unprimeable number, because it can be changed into a prime (28081649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7020409 + ... + 7020412.

Almost surely, 2^28081642 is an apocalyptic number.

28081642 is a deficient number, since it is larger than the sum of its proper divisors (14040824).

28081642 is a wasteful number, since it uses less digits than its factorization.

28081642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14040823.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 28081642 is about 5299.2114507727. The cubic root of 28081642 is about 303.9537455596.

The spelling of 28081642 in words is "twenty-eight million, eighty-one thousand, six hundred forty-two".