1972009591 has 4 divisors (see below), whose sum is σ = 1972104552. Its totient is φ = 1971914632.

The previous prime is 1972009561. The next prime is 1972009607. The reversal of 1972009591 is 1959002791.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1959002791 = 487 ⋅4022593.

It is a cyclic number.

It is not a de Polignac number, because 1972009591 - 2⁷ = 1972009463 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1972009561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1465 + ... + 62818.

It is an arithmetic number, because the mean of its divisors is an integer number (493026138).

Almost surely, 2^1972009591 is an apocalyptic number.

1972009591 is a deficient number, since it is larger than the sum of its proper divisors (94961).

1972009591 is an equidigital number, since it uses as much as digits as its factorization.

1972009591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94960.

The product of its (nonzero) digits is 51030, while the sum is 43.

The square root of 1972009591 is about 44407.3146114466. The cubic root of 1972009591 is about 1254.0157976265.

The spelling of 1972009591 in words is "one billion, nine hundred seventy-two million, nine thousand, five hundred ninety-one".