19978573 has 4 divisors (see below), whose sum is σ = 20124540. Its totient is φ = 19832608.

The previous prime is 19978571. The next prime is 19978577. The reversal of 19978573 is 37587991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37587991 = 7 ⋅5369713.

It can be written as a sum of positive squares in 2 ways, for example, as 6340324 + 13638249 = 2518^2 + 3693^2 .

It is a cyclic number.

It is not a de Polignac number, because 19978573 - 2¹ = 19978571 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19978571) 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, 72778 + ... + 73051.

It is an arithmetic number, because the mean of its divisors is an integer number (5031135).

Almost surely, 2^19978573 is an apocalyptic number.

It is an amenable number.

19978573 is a deficient number, since it is larger than the sum of its proper divisors (145967).

19978573 is a wasteful number, since it uses less digits than its factorization.

19978573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145966.

The product of its digits is 476280, while the sum is 49.

The square root of 19978573 is about 4469.7397015934. The cubic root of 19978573 is about 271.3447906442.

The spelling of 19978573 in words is "nineteen million, nine hundred seventy-eight thousand, five hundred seventy-three".