40235721 has 4 divisors (see below), whose sum is σ = 53647632. Its totient is φ = 26823812.

The previous prime is 40235707. The next prime is 40235729. The reversal of 40235721 is 12753204.

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 40235721 - 2⁷ = 40235593 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 40235691 and 40235700.

It is not an unprimeable number, because it can be changed into a prime (40235729) 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, 6705951 + ... + 6705956.

It is an arithmetic number, because the mean of its divisors is an integer number (13411908).

Almost surely, 2^40235721 is an apocalyptic number.

It is an amenable number.

40235721 is a deficient number, since it is larger than the sum of its proper divisors (13411911).

40235721 is a wasteful number, since it uses less digits than its factorization.

40235721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13411910.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 40235721 is about 6343.1633275520. The cubic root of 40235721 is about 342.6656694033.

Adding to 40235721 its reverse (12753204), we get a palindrome (52988925).

The spelling of 40235721 in words is "forty million, two hundred thirty-five thousand, seven hundred twenty-one".