40218521 has 8 divisors (see below), whose sum is σ = 46231104. Its totient is φ = 34272720.

The previous prime is 40218517. The next prime is 40218569. The reversal of 40218521 is 12581204.

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 40218521 - 2² = 40218517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40218571) 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, 15395 + ... + 17816.

It is an arithmetic number, because the mean of its divisors is an integer number (5778888).

Almost surely, 2^40218521 is an apocalyptic number.

It is an amenable number.

40218521 is a deficient number, since it is larger than the sum of its proper divisors (6012583).

40218521 is a wasteful number, since it uses less digits than its factorization.

40218521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33391.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 40218521 is about 6341.8073922187. The cubic root of 40218521 is about 342.6168347741.

Adding to 40218521 its reverse (12581204), we get a palindrome (52799725).

The spelling of 40218521 in words is "forty million, two hundred eighteen thousand, five hundred twenty-one".