40147921 has 6 divisors (see below), whose sum is σ = 44129666. Its totient is φ = 36498000.

The previous prime is 40147909. The next prime is 40147927. The reversal of 40147921 is 12974104.

40147921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 40144896 + 3025 = 6336^2 + 55^2 .

It is not a de Polignac number, because 40147921 - 2⁵ = 40147889 is a prime.

It is a super-2 number, since 2×40147921² = 3223711121244482, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 40147921.

It is not an unprimeable number, because it can be changed into a prime (40147927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 165780 + ... + 166021.

Almost surely, 2^40147921 is an apocalyptic number.

It is an amenable number.

40147921 is a deficient number, since it is larger than the sum of its proper divisors (3981745).

40147921 is a wasteful number, since it uses less digits than its factorization.

40147921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331823 (or 331812 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 40147921 is about 6336.2387107810. The cubic root of 40147921 is about 342.4162396629.

It can be divided in two parts, 4014 and 7921, that added together give a triangular number (11935 = T₁₅₄).

The spelling of 40147921 in words is "forty million, one hundred forty-seven thousand, nine hundred twenty-one".