19878401 has 4 divisors (see below), whose sum is σ = 19908612. Its totient is φ = 19848192.

The previous prime is 19878379. The next prime is 19878407. The reversal of 19878401 is 10487891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10487891 = 599 ⋅17509.

It can be written as a sum of positive squares in 2 ways, for example, as 2027776 + 17850625 = 1424^2 + 4225^2 .

It is a cyclic number.

It is not a de Polignac number, because 19878401 - 2⁶ = 19878337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19878407) 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, 14096 + ... + 15441.

It is an arithmetic number, because the mean of its divisors is an integer number (4977153).

Almost surely, 2^19878401 is an apocalyptic number.

It is an amenable number.

19878401 is a deficient number, since it is larger than the sum of its proper divisors (30211).

19878401 is an equidigital number, since it uses as much as digits as its factorization.

19878401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30210.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 19878401 is about 4458.5200459345. The cubic root of 19878401 is about 270.8905255365.

The spelling of 19878401 in words is "nineteen million, eight hundred seventy-eight thousand, four hundred one".