40405000721 has 4 divisors (see below), whose sum is σ = 41067377844. Its totient is φ = 39742623600.

The previous prime is 40405000693. The next prime is 40405000747. The reversal of 40405000721 is 12700050404.

40405000721 = 142135² + 142136².

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

It can be written as a sum of positive squares in 2 ways, for example, as 20202642496 + 20202358225 = 142136^2 + 142135^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40405000721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40405000421) 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, 331188470 + ... + 331188591.

It is an arithmetic number, because the mean of its divisors is an integer number (10266844461).

Almost surely, 2^40405000721 is an apocalyptic number.

40405000721 is the 142136-th centered square number.

It is an amenable number.

40405000721 is a deficient number, since it is larger than the sum of its proper divisors (662377123).

40405000721 is an equidigital number, since it uses as much as digits as its factorization.

40405000721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662377122.

The product of its (nonzero) digits is 1120, while the sum is 23.

The spelling of 40405000721 in words is "forty billion, four hundred five million, seven hundred twenty-one", and thus it is an aban number.