1355721 has 8 divisors (see below), whose sum is σ = 1870080. Its totient is φ = 872592.

The previous prime is 1355713. The next prime is 1355741. The reversal of 1355721 is 1275531.

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

It is not a de Polignac number, because 1355721 - 2³ = 1355713 is a prime.

1355721 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1355691 and 1355700.

It is not an unprimeable number, because it can be changed into a prime (1355741) 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, 7705 + ... + 7878.

It is an arithmetic number, because the mean of its divisors is an integer number (233760).

2^1355721 is an apocalyptic number.

It is an amenable number.

1355721 is a deficient number, since it is larger than the sum of its proper divisors (514359).

1355721 is a wasteful number, since it uses less digits than its factorization.

1355721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15615.

The product of its digits is 1050, while the sum is 24.

The square root of 1355721 is about 1164.3543275138. The cubic root of 1355721 is about 110.6768460097.

The spelling of 1355721 in words is "one million, three hundred fifty-five thousand, seven hundred twenty-one".