40438921 has 4 divisors (see below), whose sum is σ = 40546000. Its totient is φ = 40331844.

The previous prime is 40438889. The next prime is 40438927. The reversal of 40438921 is 12983404.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 40438921 - 2⁵ = 40438889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40438927) 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, 52971 + ... + 53728.

It is an arithmetic number, because the mean of its divisors is an integer number (10136500).

Almost surely, 2^40438921 is an apocalyptic number.

It is an amenable number.

40438921 is a deficient number, since it is larger than the sum of its proper divisors (107079).

40438921 is a wasteful number, since it uses less digits than its factorization.

40438921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107078.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 40438921 is about 6359.1604005560. The cubic root of 40438921 is about 343.2415488672.

The spelling of 40438921 in words is "forty million, four hundred thirty-eight thousand, nine hundred twenty-one".