1979640 has 160 divisors (see below), whose sum is σ = 7318080. Its totient is φ = 476928.

The previous prime is 1979617. The next prime is 1979683. The reversal of 1979640 is 469791.

1979640 is a `hidden beast` number, since 1 + 9 + 7 + 9 + 640 = 666.

It is a super-3 number, since 3×1979640³ = 23274476213332032000, which contains 333 as substring.

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

It is a zygodrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 1979595 and 1979604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 42097 + ... + 42143.

It is an arithmetic number, because the mean of its divisors is an integer number (45738).

2^1979640 is an apocalyptic number.

1979640 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 1979640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3659040).

1979640 is an abundant number, since it is smaller than the sum of its proper divisors (5338440).

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

1979640 is a wasteful number, since it uses less digits than its factorization.

1979640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83 (or 70 counting only the distinct ones).

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

The square root of 1979640 is about 1406.9968017021. The cubic root of 1979640 is about 125.5631127562.

The spelling of 1979640 in words is "one million, nine hundred seventy-nine thousand, six hundred forty".