1231720 has 64 divisors (see below), whose sum is σ = 3265920. Its totient is φ = 409344.

The previous prime is 1231709. The next prime is 1231721. The reversal of 1231720 is 271321.

1231720 = T₂₉ + T₃₀ + ... + T₁₉₄.

It is a happy number.

1231720 is nontrivially palindromic in base 6.

It is a junction number, because it is equal to n+sod(n) for n = 1231694 and 1231703.

It is not an unprimeable number, because it can be changed into a prime (1231721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14799 + ... + 14881.

It is an arithmetic number, because the mean of its divisors is an integer number (51030).

2^1231720 is an apocalyptic number.

1231720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1231720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1632960).

1231720 is an abundant number, since it is smaller than the sum of its proper divisors (2034200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1231720 is a wasteful number, since it uses less digits than its factorization.

1231720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 1231720 is about 1109.8288156288. The cubic root of 1231720 is about 107.1940462276.

The spelling of 1231720 in words is "one million, two hundred thirty-one thousand, seven hundred twenty".