43521921 has 16 divisors (see below), whose sum is σ = 68270400. Its totient is φ = 27307584.

The previous prime is 43521917. The next prime is 43521937. The reversal of 43521921 is 12912534.

It is not a de Polignac number, because 43521921 - 2² = 43521917 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (43521901) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46951 + ... + 47868.

It is an arithmetic number, because the mean of its divisors is an integer number (4266900).

Almost surely, 2^43521921 is an apocalyptic number.

It is an amenable number.

43521921 is a deficient number, since it is larger than the sum of its proper divisors (24748479).

43521921 is a wasteful number, since it uses less digits than its factorization.

43521921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94845 (or 94839 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 43521921 is about 6597.1145965490. The cubic root of 43521921 is about 351.7515491314.

The spelling of 43521921 in words is "forty-three million, five hundred twenty-one thousand, nine hundred twenty-one".