71640269649 has 27 divisors (see below), whose sum is σ = 112069058907. Its totient is φ = 44079896016.

The previous prime is 71640269621. The next prime is 71640269663. The reversal of 71640269649 is 94696204617.

It is a happy number.

The square root of 71640269649 is 267657.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 10597673025 + 61042596624 = 102945^2 + 247068^2 .

It is not a de Polignac number, because 71640269649 - 2²¹ = 71638172497 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 71640269595 and 71640269604.

It is not an unprimeable number, because it can be changed into a prime (71640269689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 10435192 + ... + 10442054.

Almost surely, 2^71640269649 is an apocalyptic number.

71640269649 is the 267657-th square number.

71640269649 is the 133829-th centered octagonal number.

It is an amenable number.

71640269649 is a deficient number, since it is larger than the sum of its proper divisors (40428789258).

71640269649 is an frugal number, since it uses more digits than its factorization.

71640269649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13758 (or 6879 counting only the distinct ones).

The product of its (nonzero) digits is 3919104, while the sum is 54.

The spelling of 71640269649 in words is "seventy-one billion, six hundred forty million, two hundred sixty-nine thousand, six hundred forty-nine".