1231781497872 has 160 divisors (see below), whose sum is σ = 3266574925824. Its totient is φ = 399790195200.

The previous prime is 1231781497819. The next prime is 1231781497889. The reversal of 1231781497872 is 2787941871321.

It is a happy number.

It is a super-3 number, since 3×1231781497872³ (a number of 37 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 386015797 + ... + 386018987.

Almost surely, 2^{1231781497872} is an apocalyptic number.

1231781497872 is a gapful number since it is divisible by the number (12) 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 1231781497872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1633287462912).

1231781497872 is an abundant number, since it is smaller than the sum of its proper divisors (2034793427952).

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

1231781497872 is a wasteful number, since it uses less digits than its factorization.

1231781497872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4077 (or 4071 counting only the distinct ones).

The product of its digits is 9483264, while the sum is 60.

The spelling of 1231781497872 in words is "one trillion, two hundred thirty-one billion, seven hundred eighty-one million, four hundred ninety-seven thousand, eight hundred seventy-two".