840872494081 has 9 divisors (see below), whose sum is σ = 845474121219. Its totient is φ = 836295792000.

The previous prime is 840872494073. The next prime is 840872494087. The reversal of 840872494081 is 180494278048.

The square root of 840872494081 is 916991.

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., 485751847681 + 355120646400 = 696959^2 + 595920^2 .

It is not a de Polignac number, because 840872494081 - 2³ = 840872494073 is a prime.

It is a super-2 number, since 2×840872494081² (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 (840872494087) 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, 175142881 + ... + 175147681.

Almost surely, 2^840872494081 is an apocalyptic number.

840872494081 is the 916991-st square number.

840872494081 is the 458496-th centered octagonal number.

It is an amenable number.

840872494081 is a deficient number, since it is larger than the sum of its proper divisors (4601627138).

840872494081 is an frugal number, since it uses more digits than its factorization.

840872494081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9984 (or 4992 counting only the distinct ones).

The product of its (nonzero) digits is 4128768, while the sum is 55.

The spelling of 840872494081 in words is "eight hundred forty billion, eight hundred seventy-two million, four hundred ninety-four thousand, eighty-one".