19640720 has 60 divisors (see below), whose sum is σ = 50218140. Its totient is φ = 7138560.

The previous prime is 19640713. The next prime is 19640741. The reversal of 19640720 is 2704691.

It can be written as a sum of positive squares in 2 ways, for example, as 14992384 + 4648336 = 3872^2 + 2156^2 .

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 8666 + ... + 10694.

It is an arithmetic number, because the mean of its divisors is an integer number (836969).

Almost surely, 2^19640720 is an apocalyptic number.

19640720 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 19640720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25109070).

19640720 is an abundant number, since it is smaller than the sum of its proper divisors (30577420).

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

19640720 is a wasteful number, since it uses less digits than its factorization.

19640720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2064 (or 2047 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 19640720 is about 4431.7851933504. The cubic root of 19640720 is about 269.8065372231.

The spelling of 19640720 in words is "nineteen million, six hundred forty thousand, seven hundred twenty".