40557821 has 4 divisors (see below), whose sum is σ = 40688544. Its totient is φ = 40427100.

The previous prime is 40557793. The next prime is 40557833. The reversal of 40557821 is 12875504.

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 40557821 - 2¹⁸ = 40295677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40557841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64895 + ... + 65516.

It is an arithmetic number, because the mean of its divisors is an integer number (10172136).

Almost surely, 2^40557821 is an apocalyptic number.

It is an amenable number.

40557821 is a deficient number, since it is larger than the sum of its proper divisors (130723).

40557821 is a wasteful number, since it uses less digits than its factorization.

40557821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130722.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 40557821 is about 6368.5022572030. The cubic root of 40557821 is about 343.5776235031.

The spelling of 40557821 in words is "forty million, five hundred fifty-seven thousand, eight hundred twenty-one".