1231720157332 has 72 divisors (see below), whose sum is σ = 2528298931200. Its totient is φ = 523490397696.

The previous prime is 1231720157321. The next prime is 1231720157387. The reversal of 1231720157332 is 2337510271321.

It is a junction number, because it is equal to n+sod(n) for n = 1231720157291 and 1231720157300.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 63191044 + ... + 63210532.

Almost surely, 2^{1231720157332} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1231720157332, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1264149465600).

1231720157332 is an abundant number, since it is smaller than the sum of its proper divisors (1296578773868).

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

1231720157332 is a wasteful number, since it uses less digits than its factorization.

1231720157332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22173 (or 22164 counting only the distinct ones).

The product of its (nonzero) digits is 52920, while the sum is 37.

The spelling of 1231720157332 in words is "one trillion, two hundred thirty-one billion, seven hundred twenty million, one hundred fifty-seven thousand, three hundred thirty-two".