19890078 has 32 divisors (see below), whose sum is σ = 44706816. Its totient is φ = 5853408.

The previous prime is 19890061. The next prime is 19890083. The reversal of 19890078 is 87009891.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3750 + ... + 7337.

It is an arithmetic number, because the mean of its divisors is an integer number (1397088).

Almost surely, 2^19890078 is an apocalyptic number.

19890078 is an abundant number, since it is smaller than the sum of its proper divisors (24816738).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19890078 is a wasteful number, since it uses less digits than its factorization.

19890078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11128.

The product of its (nonzero) digits is 36288, while the sum is 42.

The square root of 19890078 is about 4459.8293689333. The cubic root of 19890078 is about 270.9435574595.

It can be divided in two parts, 1989007 and 8, that added together give a triangular number (1989015 = T₁₉₉₄).

The spelling of 19890078 in words is "nineteen million, eight hundred ninety thousand, seventy-eight".