891972580249 has 15 divisors (see below), whose sum is σ = 924652074873. Its totient is φ = 860448017352.

The previous prime is 891972580243. The next prime is 891972580277. The reversal of 891972580249 is 942085279198.

The square root of 891972580249 is 944443.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2119957849 + 889852622400 = 46043^2 + 943320^2 .

It is not a de Polignac number, because 891972580249 - 2⁹ = 891972579737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (891972580243) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 794276002 + ... + 794277124.

Almost surely, 2^891972580249 is an apocalyptic number.

891972580249 is the 944443-rd square number.

891972580249 is the 472222-nd centered octagonal number.

It is an amenable number.

891972580249 is a deficient number, since it is larger than the sum of its proper divisors (32679494624).

891972580249 is an frugal number, since it uses more digits than its factorization.

891972580249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2362 (or 1152 counting only the distinct ones).

The product of its (nonzero) digits is 26127360, while the sum is 64.

Multiplying 891972580249 by its sum of digits (64), we get a square (57086245135936 = 7555544²).

The spelling of 891972580249 in words is "eight hundred ninety-one billion, nine hundred seventy-two million, five hundred eighty thousand, two hundred forty-nine".