1720990 has 16 divisors (see below), whose sum is σ = 3127248. Its totient is φ = 681856.

The previous prime is 1720973. The next prime is 1720991. The reversal of 1720990 is 990271.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1720991) 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, 369 + ... + 1891.

It is an arithmetic number, because the mean of its divisors is an integer number (195453).

2^1720990 is an apocalyptic number.

1720990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1720990 is a deficient number, since it is larger than the sum of its proper divisors (1406258).

1720990 is a wasteful number, since it uses less digits than its factorization.

1720990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1643.

The product of its (nonzero) digits is 1134, while the sum is 28.

The square root of 1720990 is about 1311.8650845266. The cubic root of 1720990 is about 119.8375115600.

The spelling of 1720990 in words is "one million, seven hundred twenty thousand, nine hundred ninety".