1864191421 has 2 divisors, whose sum is σ = 1864191422. Its totient is φ = 1864191420.

The previous prime is 1864191359. The next prime is 1864191449. The reversal of 1864191421 is 1241914681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1830898521 + 33292900 = 42789^2 + 5770^2 .

It is a cyclic number.

It is not a de Polignac number, because 1864191421 - 2¹⁹ = 1863667133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1864191481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 932095710 + 932095711.

It is an arithmetic number, because the mean of its divisors is an integer number (932095711).

Almost surely, 2^1864191421 is an apocalyptic number.

It is an amenable number.

1864191421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1864191421 is an equidigital number, since it uses as much as digits as its factorization.

1864191421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 37.

The square root of 1864191421 is about 43176.2830845824. The cubic root of 1864191421 is about 1230.7320253113.

The spelling of 1864191421 in words is "one billion, eight hundred sixty-four million, one hundred ninety-one thousand, four hundred twenty-one".