1231722156 has 72 divisors (see below), whose sum is σ = 3376079616. Its totient is φ = 342377280.

The previous prime is 1231722103. The next prime is 1231722157. The reversal of 1231722156 is 6512271321.

It is not an unprimeable number, because it can be changed into a prime (1231722157) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 109641 + ... + 120351.

Almost surely, 2^1231722156 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 1231722156, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1688039808).

1231722156 is an abundant number, since it is smaller than the sum of its proper divisors (2144357460).

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

1231722156 is a wasteful number, since it uses less digits than its factorization.

1231722156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10799 (or 10760 counting only the distinct ones).

The product of its digits is 5040, while the sum is 30.

The square root of 1231722156 is about 35095.8994185931. The cubic root of 1231722156 is about 1071.9410877163.

Adding to 1231722156 its reverse (6512271321), we get a palindrome (7743993477).

The spelling of 1231722156 in words is "one billion, two hundred thirty-one million, seven hundred twenty-two thousand, one hundred fifty-six".