845404852681 has 9 divisors (see below), whose sum is σ = 855093282823. Its totient is φ = 835825009360.

The previous prime is 845404852651. The next prime is 845404852687. The reversal of 845404852681 is 186258404548.

It is a happy number.

The square root of 845404852681 is 919459.

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., 162335662281 + 683069190400 = 402909^2 + 826480^2 .

It is not a de Polignac number, because 845404852681 - 2¹³ = 845404844489 is a prime.

It is a super-2 number, since 2×845404852681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (845404852687) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 81826686 + ... + 81837016.

Almost surely, 2^845404852681 is an apocalyptic number.

845404852681 is the 919459-th square number.

845404852681 is the 459730-th centered octagonal number.

It is an amenable number.

845404852681 is a deficient number, since it is larger than the sum of its proper divisors (9688430142).

845404852681 is an frugal number, since it uses more digits than its factorization.

845404852681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20840 (or 10420 counting only the distinct ones).

The product of its (nonzero) digits is 9830400, while the sum is 55.

The spelling of 845404852681 in words is "eight hundred forty-five billion, four hundred four million, eight hundred fifty-two thousand, six hundred eighty-one".