257772321721 has 8 divisors (see below), whose sum is σ = 266670169920. Its totient is φ = 248875083408.

The previous prime is 257772321713. The next prime is 257772321739. The reversal of 257772321721 is 127123277752.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 257772321721 - 2³ = 257772321713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257772321761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 810630 + ... + 1082896.

It is an arithmetic number, because the mean of its divisors is an integer number (33333771240).

Almost surely, 2^257772321721 is an apocalyptic number.

It is an amenable number.

257772321721 is a deficient number, since it is larger than the sum of its proper divisors (8897848199).

257772321721 is a wasteful number, since it uses less digits than its factorization.

257772321721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304943.

The product of its digits is 576240, while the sum is 46.

The spelling of 257772321721 in words is "two hundred fifty-seven billion, seven hundred seventy-two million, three hundred twenty-one thousand, seven hundred twenty-one".