19782001 has 4 divisors (see below), whose sum is σ = 20642112. Its totient is φ = 18921892.

The previous prime is 19781989. The next prime is 19782011. The reversal of 19782001 is 10028791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 10028791 = 487 ⋅20593.

It is a cyclic number.

It is not a de Polignac number, because 19782001 - 2⁵ = 19781969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19782011) 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, 430021 + ... + 430066.

It is an arithmetic number, because the mean of its divisors is an integer number (5160528).

Almost surely, 2^19782001 is an apocalyptic number.

It is an amenable number.

19782001 is a deficient number, since it is larger than the sum of its proper divisors (860111).

19782001 is an equidigital number, since it uses as much as digits as its factorization.

19782001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 860110.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 19782001 is about 4447.6961451970. The cubic root of 19782001 is about 270.4519226251.

The spelling of 19782001 in words is "nineteen million, seven hundred eighty-two thousand, one".