19842640 has 20 divisors (see below), whose sum is σ = 46134324. Its totient is φ = 7937024.

The previous prime is 19842637. The next prime is 19842643. The reversal of 19842640 is 4624891.

It is an interprime number because it is at equal distance from previous prime (19842637) and next prime (19842643).

It can be written as a sum of positive squares in 2 ways, for example, as 14807104 + 5035536 = 3848^2 + 2244^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 19842596 and 19842605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19842643) 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 3 ways as a sum of consecutive naturals, for example, 123937 + ... + 124096.

Almost surely, 2^19842640 is an apocalyptic number.

19842640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19842640 is an abundant number, since it is smaller than the sum of its proper divisors (26291684).

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

19842640 is a wasteful number, since it uses less digits than its factorization.

19842640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248046 (or 248040 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 19842640 is about 4454.5078291546. The cubic root of 19842640 is about 270.7279851153.

It can be divided in two parts, 1984 and 2640, that added together give a square (4624 = 68²).

The spelling of 19842640 in words is "nineteen million, eight hundred forty-two thousand, six hundred forty".