28106491 has 32 divisors (see below), whose sum is σ = 37048320. Its totient is φ = 20736000.

The previous prime is 28106489. The next prime is 28106503. The reversal of 28106491 is 19460182.

It is a happy number.

It is a 11-Lehmer number, since φ(28106491) divides (28106491-1)¹¹.

It is a cyclic number.

It is not a de Polignac number, because 28106491 - 2¹ = 28106489 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28106411) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 69891 + ... + 70291.

It is an arithmetic number, because the mean of its divisors is an integer number (1157760).

Almost surely, 2^28106491 is an apocalyptic number.

28106491 is a deficient number, since it is larger than the sum of its proper divisors (8941829).

28106491 is a wasteful number, since it uses less digits than its factorization.

28106491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 28106491 is about 5301.5555264469. Note that the first 4 decimals coincide. The cubic root of 28106491 is about 304.0433737455.

The spelling of 28106491 in words is "twenty-eight million, one hundred six thousand, four hundred ninety-one".