1904878081 has 4 divisors (see below), whose sum is σ = 1951338564. Its totient is φ = 1858417600.

The previous prime is 1904878069. The next prime is 1904878091. The reversal of 1904878081 is 1808784091.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1808784091 = 2963 ⋅610457.

It can be written as a sum of positive squares in 2 ways, for example, as 139617856 + 1765260225 = 11816^2 + 42015^2 .

It is a cyclic number.

It is not a de Polignac number, because 1904878081 - 2²³ = 1896489473 is a prime.

It is a super-2 number, since 2×1904878081² = 7257121006948485122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1904878091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23230180 + ... + 23230261.

It is an arithmetic number, because the mean of its divisors is an integer number (487834641).

Almost surely, 2^1904878081 is an apocalyptic number.

It is an amenable number.

1904878081 is a deficient number, since it is larger than the sum of its proper divisors (46460483).

1904878081 is an equidigital number, since it uses as much as digits as its factorization.

1904878081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46460482.

The product of its (nonzero) digits is 129024, while the sum is 46.

The square root of 1904878081 is about 43644.9089929169. The cubic root of 1904878081 is about 1239.6213900037.

The spelling of 1904878081 in words is "one billion, nine hundred four million, eight hundred seventy-eight thousand, eighty-one".