17978143920 has 80 divisors (see below), whose sum is σ = 60798822912. Its totient is φ = 4358337280.

The previous prime is 17978143891. The next prime is 17978143927. The reversal of 17978143920 is 2934187971.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (17978143927) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3402312 + ... + 3407591.

Almost surely, 2^17978143920 is an apocalyptic number.

17978143920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

17978143920 is an abundant number, since it is smaller than the sum of its proper divisors (42820678992).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

17978143920 is a wasteful number, since it uses less digits than its factorization.

17978143920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6809930 (or 6809924 counting only the distinct ones).

The product of its (nonzero) digits is 762048, while the sum is 51.

The spelling of 17978143920 in words is "seventeen billion, nine hundred seventy-eight million, one hundred forty-three thousand, nine hundred twenty".