19863640 has 32 divisors (see below), whose sum is σ = 44992080. Its totient is φ = 7892352.

The previous prime is 19863629. The next prime is 19863647. The reversal of 19863640 is 4636891.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 19863640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19863647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4699 + ... + 7861.

Almost surely, 2^19863640 is an apocalyptic number.

19863640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19863640 is an abundant number, since it is smaller than the sum of its proper divisors (25128440).

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

19863640 is a wasteful number, since it uses less digits than its factorization.

19863640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3331 (or 3327 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 19863640 is about 4456.8643685892. The cubic root of 19863640 is about 270.8234576807.

It can be divided in two parts, 19863 and 640, that added together give a triangular number (20503 = T₂₀₂).

The spelling of 19863640 in words is "nineteen million, eight hundred sixty-three thousand, six hundred forty".