1721145 has 8 divisors (see below), whose sum is σ = 2753856. Its totient is φ = 917936.

The previous prime is 1721143. The next prime is 1721147. The reversal of 1721145 is 5411271.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1721143) and next prime (1721147).

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 1721145 - 2¹ = 1721143 is a prime.

It is a super-2 number, since 2×1721145² = 5924680222050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1721143) 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, 57357 + ... + 57386.

It is an arithmetic number, because the mean of its divisors is an integer number (344232).

2^1721145 is an apocalyptic number.

1721145 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1721145 is a deficient number, since it is larger than the sum of its proper divisors (1032711).

1721145 is a wasteful number, since it uses less digits than its factorization.

1721145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114751.

The product of its digits is 280, while the sum is 21.

The square root of 1721145 is about 1311.9241593934. The cubic root of 1721145 is about 119.8411091515.

The spelling of 1721145 in words is "one million, seven hundred twenty-one thousand, one hundred forty-five".