645842071449 has 81 divisors (see below), whose sum is σ = 1030916424447. Its totient is φ = 389528976672.

The previous prime is 645842071447. The next prime is 645842071489. The reversal of 645842071449 is 944170248546.

The square root of 645842071449 is 803643.

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

645842071449 is a `hidden beast` number, since 6 + 4 + 584 + 2 + 0 + 7 + 14 + 49 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2105433225 + 643736638224 = 45885^2 + 802332^2 .

It is not a de Polignac number, because 645842071449 - 2¹ = 645842071447 is a prime.

It is a super-2 number, since 2×645842071449² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 645842071395 and 645842071404.

It is not an unprimeable number, because it can be changed into a prime (645842071447) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 1053575667 + ... + 1053576279.

Almost surely, 2^645842071449 is an apocalyptic number.

645842071449 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

645842071449 is the 803643-rd square number.

645842071449 is the 401822-nd centered octagonal number.

It is an amenable number.

645842071449 is a deficient number, since it is larger than the sum of its proper divisors (385074352998).

645842071449 is an equidigital number, since it uses as much as digits as its factorization.

645842071449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1316 (or 658 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 54.

The spelling of 645842071449 in words is "six hundred forty-five billion, eight hundred forty-two million, seventy-one thousand, four hundred forty-nine".