19781425247 has 4 divisors (see below), whose sum is σ = 19782122256. Its totient is φ = 19780728240.

The previous prime is 19781425229. The next prime is 19781425249. The reversal of 19781425247 is 74252418791.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19781425247 is a prime.

It is a super-2 number, since 2×19781425247² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19781425195 and 19781425204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19781425249) 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, 304043 + ... + 363324.

It is an arithmetic number, because the mean of its divisors is an integer number (4945530564).

Almost surely, 2^19781425247 is an apocalyptic number.

19781425247 is a deficient number, since it is larger than the sum of its proper divisors (697009).

19781425247 is an equidigital number, since it uses as much as digits as its factorization.

19781425247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 697008.

The product of its digits is 1128960, while the sum is 50.

The spelling of 19781425247 in words is "nineteen billion, seven hundred eighty-one million, four hundred twenty-five thousand, two hundred forty-seven".