40641721 has 2 divisors, whose sum is σ = 40641722. Its totient is φ = 40641720.

The previous prime is 40641719. The next prime is 40641803. The reversal of 40641721 is 12714604.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 35236096 + 5405625 = 5936^2 + 2325^2 .

It is a cyclic number.

It is not a de Polignac number, because 40641721 - 2¹ = 40641719 is a prime.

Together with 40641719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (40641221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20320860 + 20320861.

It is an arithmetic number, because the mean of its divisors is an integer number (20320861).

Almost surely, 2^40641721 is an apocalyptic number.

It is an amenable number.

40641721 is a deficient number, since it is larger than the sum of its proper divisors (1).

40641721 is an equidigital number, since it uses as much as digits as its factorization.

40641721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 40641721 is about 6375.0859602048. The cubic root of 40641721 is about 343.8143744562.

The spelling of 40641721 in words is "forty million, six hundred forty-one thousand, seven hundred twenty-one".