40891821 has 8 divisors (see below), whose sum is σ = 56281344. Its totient is φ = 26381760.

The previous prime is 40891789. The next prime is 40891831. The reversal of 40891821 is 12819804.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 40891821 - 2⁵ = 40891789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40891831) 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, 219756 + ... + 219941.

It is an arithmetic number, because the mean of its divisors is an integer number (7035168).

Almost surely, 2^40891821 is an apocalyptic number.

It is an amenable number.

40891821 is a deficient number, since it is larger than the sum of its proper divisors (15389523).

40891821 is a wasteful number, since it uses less digits than its factorization.

40891821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 439731.

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 40891821 is about 6394.6712972599. The cubic root of 40891821 is about 344.5181848095.

It can be divided in two parts, 408 and 91821, that added together give a palindrome (92229).

The spelling of 40891821 in words is "forty million, eight hundred ninety-one thousand, eight hundred twenty-one".