19972779 has 4 divisors (see below), whose sum is σ = 26630376. Its totient is φ = 13315184.

The previous prime is 19972753. The next prime is 19972787. The reversal of 19972779 is 97727991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19972779 - 2⁵ = 19972747 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19972709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3328794 + ... + 3328799.

It is an arithmetic number, because the mean of its divisors is an integer number (6657594).

Almost surely, 2^19972779 is an apocalyptic number.

19972779 is a deficient number, since it is larger than the sum of its proper divisors (6657597).

19972779 is an equidigital number, since it uses as much as digits as its factorization.

19972779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6657596.

The product of its digits is 500094, while the sum is 51.

The square root of 19972779 is about 4469.0915184185. The cubic root of 19972779 is about 271.3185571435.

The spelling of 19972779 in words is "nineteen million, nine hundred seventy-two thousand, seven hundred seventy-nine".