1979721 has 12 divisors (see below), whose sum is σ = 2965872. Its totient is φ = 1319652.

The previous prime is 1979717. The next prime is 1979723. The reversal of 1979721 is 1279791.

It is not a de Polignac number, because 1979721 - 2² = 1979717 is a prime.

It is a super-3 number, since 3×1979721³ = 23277333262661467083, which contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (1979723) 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 11 ways as a sum of consecutive naturals, for example, 3831 + ... + 4316.

It is an arithmetic number, because the mean of its divisors is an integer number (247156).

2^1979721 is an apocalyptic number.

It is an amenable number.

1979721 is a deficient number, since it is larger than the sum of its proper divisors (986151).

1979721 is an frugal number, since it uses more digits than its factorization.

1979721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8162 (or 8150 counting only the distinct ones).

The product of its digits is 7938, while the sum is 36.

The square root of 1979721 is about 1407.0255861213. The cubic root of 1979721 is about 125.5648252685.

The spelling of 1979721 in words is "one million, nine hundred seventy-nine thousand, seven hundred twenty-one".