40220721 has 24 divisors (see below), whose sum is σ = 61379136. Its totient is φ = 25328160.

The previous prime is 40220711. The next prime is 40220743. The reversal of 40220721 is 12702204.

It is not a de Polignac number, because 40220721 - 2⁵ = 40220689 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 40220694 and 40220703.

It is not an unprimeable number, because it can be changed into a prime (40220711) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16011 + ... + 18351.

It is an arithmetic number, because the mean of its divisors is an integer number (2557464).

Almost surely, 2^40220721 is an apocalyptic number.

It is an amenable number.

40220721 is a deficient number, since it is larger than the sum of its proper divisors (21158415).

40220721 is a wasteful number, since it uses less digits than its factorization.

40220721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2453 (or 2450 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 40220721 is about 6341.9808419767. The cubic root of 40220721 is about 342.6230818403.

Adding to 40220721 its reverse (12702204), we get a palindrome (52922925).

The spelling of 40220721 in words is "forty million, two hundred twenty thousand, seven hundred twenty-one".