40011721 has 4 divisors (see below), whose sum is σ = 40099732. Its totient is φ = 39923712.

The previous prime is 40011709. The next prime is 40011733. The reversal of 40011721 is 12711004.

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

It is an interprime number because it is at equal distance from previous prime (40011709) and next prime (40011733).

It can be written as a sum of positive squares in 2 ways, for example, as 32936121 + 7075600 = 5739^2 + 2660^2 .

It is a 4-Lehmer number, since φ(40011721) divides (40011721-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 40011721 - 2⁷ = 40011593 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 40011695 and 40011704.

It is not an unprimeable number, because it can be changed into a prime (40011781) 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, 43320 + ... + 44233.

It is an arithmetic number, because the mean of its divisors is an integer number (10024933).

Almost surely, 2^40011721 is an apocalyptic number.

It is an amenable number.

40011721 is a deficient number, since it is larger than the sum of its proper divisors (88011).

40011721 is an equidigital number, since it uses as much as digits as its factorization.

40011721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88010.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 40011721 is about 6325.4818788769. The cubic root of 40011721 is about 342.0285904532.

Adding to 40011721 its reverse (12711004), we get a palindrome (52722725).

It can be divided in two parts, 400 and 11721, that added together give a palindrome (12121).

The spelling of 40011721 in words is "forty million, eleven thousand, seven hundred twenty-one".