19778699640 has 512 divisors, whose sum is σ = 73766246400. Its totient is φ = 4140564480.

The previous prime is 19778699621. The next prime is 19778699651. The reversal of 19778699640 is 4699687791.

It is a super-2 number, since 2×19778699640² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 150982375 + ... + 150982505.

It is an arithmetic number, because the mean of its divisors is an integer number (144074700).

Almost surely, 2^19778699640 is an apocalyptic number.

19778699640 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 19778699640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36883123200).

19778699640 is an abundant number, since it is smaller than the sum of its proper divisors (53987546760).

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

19778699640 is a wasteful number, since it uses less digits than its factorization.

19778699640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375 (or 371 counting only the distinct ones).

The product of its (nonzero) digits is 41150592, while the sum is 66.

The spelling of 19778699640 in words is "nineteen billion, seven hundred seventy-eight million, six hundred ninety-nine thousand, six hundred forty".