19640628 has 72 divisors (see below), whose sum is σ = 57744960. Its totient is φ = 5512320.

The previous prime is 19640603. The next prime is 19640633. The reversal of 19640628 is 82604691.

19640628 is a `hidden beast` number, since 1 + 9 + 640 + 6 + 2 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 19640592 and 19640601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14208 + ... + 15528.

Almost surely, 2^19640628 is an apocalyptic number.

19640628 is a gapful number since it is divisible by the number (18) 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 19640628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28872480).

19640628 is an abundant number, since it is smaller than the sum of its proper divisors (38104332).

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

19640628 is a wasteful number, since it uses less digits than its factorization.

19640628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1397 (or 1392 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 19640628 is about 4431.7748137738. The cubic root of 19640628 is about 269.8061159513.

The spelling of 19640628 in words is "nineteen million, six hundred forty thousand, six hundred twenty-eight".