1721345979256 has 16 divisors (see below), whose sum is σ = 3228117414840. Its totient is φ = 860514668640.

The previous prime is 1721345979191. The next prime is 1721345979281. The reversal of 1721345979256 is 6529795431271.

It is a junction number, because it is equal to n+sod(n) for n = 1721345979194 and 1721345979203.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19743910 + ... + 19830901.

Almost surely, 2^{1721345979256} is an apocalyptic number.

It is an amenable number.

1721345979256 is a deficient number, since it is larger than the sum of its proper divisors (1506771435584).

1721345979256 is a wasteful number, since it uses less digits than its factorization.

1721345979256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39580254 (or 39580250 counting only the distinct ones).

The product of its digits is 28576800, while the sum is 61.

The spelling of 1721345979256 in words is "one trillion, seven hundred twenty-one billion, three hundred forty-five million, nine hundred seventy-nine thousand, two hundred fifty-six".