28891390 has 16 divisors (see below), whose sum is σ = 56732400. Its totient is φ = 10505920.

The previous prime is 28891367. The next prime is 28891403. The reversal of 28891390 is 9319882.

It is a super-2 number, since 2×28891390² = 1669424832264200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131215 + ... + 131434.

It is an arithmetic number, because the mean of its divisors is an integer number (3545775).

Almost surely, 2^28891390 is an apocalyptic number.

28891390 is a deficient number, since it is larger than the sum of its proper divisors (27841010).

28891390 is a wasteful number, since it uses less digits than its factorization.

28891390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262667.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 28891390 is about 5375.0711623196. The cubic root of 28891390 is about 306.8476575481.

The spelling of 28891390 in words is "twenty-eight million, eight hundred ninety-one thousand, three hundred ninety".