1891572461 has 2 divisors, whose sum is σ = 1891572462. Its totient is φ = 1891572460.

The previous prime is 1891572421. The next prime is 1891572523. The reversal of 1891572461 is 1642751981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1442556361 + 449016100 = 37981^2 + 21190^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1891572461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1891572401) 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 as a sum of consecutive naturals, namely, 945786230 + 945786231.

It is an arithmetic number, because the mean of its divisors is an integer number (945786231).

Almost surely, 2^1891572461 is an apocalyptic number.

It is an amenable number.

1891572461 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891572461 is an equidigital number, since it uses as much as digits as its factorization.

1891572461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 44.

The square root of 1891572461 is about 43492.2114981522. The cubic root of 1891572461 is about 1236.7283816876.

The spelling of 1891572461 in words is "one billion, eight hundred ninety-one million, five hundred seventy-two thousand, four hundred sixty-one".