19998767890 has 16 divisors (see below), whose sum is σ = 35999621208. Its totient is φ = 7999098496.

The previous prime is 19998767863. The next prime is 19998767897. The reversal of 19998767890 is 9876789991.

It is a Cunningham number, because it is equal to 141417²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 8706942721 + 11291825169 = 93311^2 + 106263^2 .

It is not an unprimeable number, because it can be changed into a prime (19998767897) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 226044 + ... + 301816.

Almost surely, 2^19998767890 is an apocalyptic number.

19998767890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19998767890 is a deficient number, since it is larger than the sum of its proper divisors (16000853318).

19998767890 is a wasteful number, since it uses less digits than its factorization.

19998767890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102173.

The product of its (nonzero) digits is 123451776, while the sum is 73.

The spelling of 19998767890 in words is "nineteen billion, nine hundred ninety-eight million, seven hundred sixty-seven thousand, eight hundred ninety".