40172891 has 4 divisors (see below), whose sum is σ = 43824984. Its totient is φ = 36520800.

The previous prime is 40172837. The next prime is 40172893. The reversal of 40172891 is 19827104.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40172891 is a prime.

It is a super-2 number, since 2×40172891² = 3227722342595762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40172893) 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, 1826030 + ... + 1826051.

It is an arithmetic number, because the mean of its divisors is an integer number (10956246).

Almost surely, 2^40172891 is an apocalyptic number.

40172891 is a deficient number, since it is larger than the sum of its proper divisors (3652093).

40172891 is a wasteful number, since it uses less digits than its factorization.

40172891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3652092.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 40172891 is about 6338.2088163771. The cubic root of 40172891 is about 342.4872135458.

Adding to 40172891 its reverse (19827104), we get a palindrome (59999995).

The spelling of 40172891 in words is "forty million, one hundred seventy-two thousand, eight hundred ninety-one".