1720631 has 4 divisors (see below), whose sum is σ = 1877064. Its totient is φ = 1564200.

The previous prime is 1720619. The next prime is 1720633. The reversal of 1720631 is 1360271.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1360271 = 11 ⋅123661.

It is not a de Polignac number, because 1720631 - 2¹⁰ = 1719607 is a prime.

It is a super-2 number, since 2×1720631² = 5921142076322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1720633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78200 + ... + 78221.

It is an arithmetic number, because the mean of its divisors is an integer number (469266).

2^1720631 is an apocalyptic number.

1720631 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1720631 is a deficient number, since it is larger than the sum of its proper divisors (156433).

1720631 is a wasteful number, since it uses less digits than its factorization.

1720631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156432.

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 1720631 is about 1311.7282492956. The cubic root of 1720631 is about 119.8291782444.

The spelling of 1720631 in words is "one million, seven hundred twenty thousand, six hundred thirty-one".