40728121 has 8 divisors (see below), whose sum is σ = 46597824. Its totient is φ = 34871280.

The previous prime is 40728109. The next prime is 40728131. The reversal of 40728121 is 12182704.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 40728121 - 2⁷ = 40727993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (40728131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4971 + ... + 10303.

It is an arithmetic number, because the mean of its divisors is an integer number (5824728).

Almost surely, 2^40728121 is an apocalyptic number.

It is an amenable number.

40728121 is a deficient number, since it is larger than the sum of its proper divisors (5869703).

40728121 is a wasteful number, since it uses less digits than its factorization.

40728121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6431.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 40728121 is about 6381.8587417774. The cubic root of 40728121 is about 344.0578396750.

The spelling of 40728121 in words is "forty million, seven hundred twenty-eight thousand, one hundred twenty-one".