40128889 has 4 divisors (see below), whose sum is σ = 40175524. Its totient is φ = 40082256.

The previous prime is 40128877. The next prime is 40128901. The reversal of 40128889 is 98882104.

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

It is an interprime number because it is at equal distance from previous prime (40128877) and next prime (40128901).

It can be written as a sum of positive squares in 2 ways, for example, as 20839225 + 19289664 = 4565^2 + 4392^2 .

It is a cyclic number.

It is not a de Polignac number, because 40128889 - 2²³ = 31740281 is a prime.

It is a super-2 number, since 2×40128889² = 3220655464748642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40128839) 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, 22002 + ... + 23755.

It is an arithmetic number, because the mean of its divisors is an integer number (10043881).

Almost surely, 2^40128889 is an apocalyptic number.

It is an amenable number.

40128889 is a deficient number, since it is larger than the sum of its proper divisors (46635).

40128889 is an equidigital number, since it uses as much as digits as its factorization.

40128889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46634.

The product of its (nonzero) digits is 36864, while the sum is 40.

The square root of 40128889 is about 6334.7366953963. The cubic root of 40128889 is about 342.3621239847.

The spelling of 40128889 in words is "forty million, one hundred twenty-eight thousand, eight hundred eighty-nine".