1375721 has 8 divisors (see below), whose sum is σ = 1421064. Its totient is φ = 1331200.

The previous prime is 1375709. The next prime is 1375723. The reversal of 1375721 is 1275731.

It can be written as a sum of positive squares in 4 ways, for example, as 1125721 + 250000 = 1061^2 + 500^2 .

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 1375721 - 2¹⁰ = 1374697 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1375723) 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, 5225 + ... + 5481.

It is an arithmetic number, because the mean of its divisors is an integer number (177633).

2^1375721 is an apocalyptic number.

It is an amenable number.

1375721 is a deficient number, since it is larger than the sum of its proper divisors (45343).

1375721 is a wasteful number, since it uses less digits than its factorization.

1375721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411.

The product of its digits is 1470, while the sum is 26.

The square root of 1375721 is about 1172.9113350974. The cubic root of 1375721 is about 111.2184373704.

The spelling of 1375721 in words is "one million, three hundred seventy-five thousand, seven hundred twenty-one".