1901865881 has 2 divisors, whose sum is σ = 1901865882. Its totient is φ = 1901865880.

The previous prime is 1901865863. The next prime is 1901865923. The reversal of 1901865881 is 1885681091.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1807950400 + 93915481 = 42520^2 + 9691^2 .

It is a cyclic number.

It is not a de Polignac number, because 1901865881 - 2⁶ = 1901865817 is a prime.

It is a super-2 number, since 2×1901865881² = 7234187658623812322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1901865281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 950932940 + 950932941.

It is an arithmetic number, because the mean of its divisors is an integer number (950932941).

Almost surely, 2^1901865881 is an apocalyptic number.

It is an amenable number.

1901865881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1901865881 is an equidigital number, since it uses as much as digits as its factorization.

1901865881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 138240, while the sum is 47.

The square root of 1901865881 is about 43610.3873062370. The cubic root of 1901865881 is about 1238.9676373192.

The spelling of 1901865881 in words is "one billion, nine hundred one million, eight hundred sixty-five thousand, eight hundred eighty-one".