40729921 has 4 divisors (see below), whose sum is σ = 41103700. Its totient is φ = 40356144.

The previous prime is 40729907. The next prime is 40729937. The reversal of 40729921 is 12992704.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 16719921 + 24010000 = 4089^2 + 4900^2 .

It is a cyclic number.

It is not a de Polignac number, because 40729921 - 2¹⁷ = 40598849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40729961) 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, 186726 + ... + 186943.

It is an arithmetic number, because the mean of its divisors is an integer number (10275925).

Almost surely, 2^40729921 is an apocalyptic number.

It is an amenable number.

40729921 is a deficient number, since it is larger than the sum of its proper divisors (373779).

40729921 is a wasteful number, since it uses less digits than its factorization.

40729921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373778.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 40729921 is about 6381.9997649640. Note that the first 3 decimals coincide. The cubic root of 40729921 is about 344.0629082040.

The spelling of 40729921 in words is "forty million, seven hundred twenty-nine thousand, nine hundred twenty-one".