1091972025 has 27 divisors (see below), whose sum is σ = 1956731439. Its totient is φ = 582120720.

The previous prime is 1091971981. The next prime is 1091972027. The reversal of 1091972025 is 5202791901.

The square root of 1091972025 is 33045.

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., 393109929 + 698862096 = 19827^2 + 26436^2 .

It is not a de Polignac number, because 1091972025 - 2¹⁹ = 1091447737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1091972027) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 494574 + ... + 496776.

Almost surely, 2^1091972025 is an apocalyptic number.

1091972025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1091972025 is the 33045-th square number.

1091972025 is the 16523-rd centered octagonal number.

It is an amenable number.

1091972025 is a deficient number, since it is larger than the sum of its proper divisors (864759414).

1091972025 is an frugal number, since it uses more digits than its factorization.

1091972025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4422 (or 2211 counting only the distinct ones).

The product of its (nonzero) digits is 11340, while the sum is 36.

The cubic root of 1091972025 is about 1029.7627332329.

Multiplying 1091972025 by its sum of digits (36), we get a square (39310992900 = 198270²).

It can be divided in two parts, 10919 and 72025, that added together give a square (82944 = 288²).

The spelling of 1091972025 in words is "one billion, ninety-one million, nine hundred seventy-two thousand, twenty-five".