19778013 has 24 divisors (see below), whose sum is σ = 29848000. Its totient is φ = 13087008.

The previous prime is 19777991. The next prime is 19778027. The reversal of 19778013 is 31087791.

It is not a de Polignac number, because 19778013 - 2⁸ = 19777757 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 (19778053) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48153 + ... + 48561.

Almost surely, 2^19778013 is an apocalyptic number.

It is an amenable number.

19778013 is a deficient number, since it is larger than the sum of its proper divisors (10069987).

19778013 is an equidigital number, since it uses as much as digits as its factorization.

19778013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 623 (or 611 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 36.

The square root of 19778013 is about 4447.2478006066. The cubic root of 19778013 is about 270.4337472687.

It can be divided in two parts, 197 and 78013, that added together give a triangular number (78210 = T₃₉₅).

The spelling of 19778013 in words is "nineteen million, seven hundred seventy-eight thousand, thirteen".