19986477840 has 480 divisors, whose sum is σ = 80068375296. Its totient is φ = 4538695680.

The previous prime is 19986477817. The next prime is 19986477943. The reversal of 19986477840 is 4877468991.

19986477840 is a `hidden beast` number, since 1 + 9 + 9 + 86 + 477 + 84 + 0 = 666.

It is a super-2 number, since 2×19986477840² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 26263060 + ... + 26263820.

Almost surely, 2^19986477840 is an apocalyptic number.

19986477840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19986477840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40034187648).

19986477840 is an abundant number, since it is smaller than the sum of its proper divisors (60081897456).

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

19986477840 is a wasteful number, since it uses less digits than its factorization.

19986477840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 989 (or 971 counting only the distinct ones).

The product of its (nonzero) digits is 24385536, while the sum is 63.

The spelling of 19986477840 in words is "nineteen billion, nine hundred eighty-six million, four hundred seventy-seven thousand, eight hundred forty".