19790640 has 60 divisors (see below), whose sum is σ = 66465984. Its totient is φ = 5277312.

The previous prime is 19790633. The next prime is 19790651. The reversal of 19790640 is 4609791.

19790640 is a `hidden beast` number, since 1 + 9 + 7 + 9 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (60).

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 = 19790595 and 19790604.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13024 + ... + 14463.

Almost surely, 2^19790640 is an apocalyptic number.

19790640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19790640 is an abundant number, since it is smaller than the sum of its proper divisors (46675344).

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

19790640 is a wasteful number, since it uses less digits than its factorization.

19790640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27506 (or 27497 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 19790640 is about 4448.6672161446. The cubic root of 19790640 is about 270.4912865925.

It can be divided in two parts, 1 and 9790640, that added together give a square (9790641 = 3129²).

The spelling of 19790640 in words is "nineteen million, seven hundred ninety thousand, six hundred forty".