1231644645 has 288 divisors, whose sum is σ = 2996248320. Its totient is φ = 460615680.

The previous prime is 1231644643. The next prime is 1231644649. The reversal of 1231644645 is 5464461321.

1231644645 is a `hidden beast` number, since 1 + 2 + 3 + 1 + 6 + 4 + 4 + 645 = 666.

It is not a de Polignac number, because 1231644645 - 2¹ = 1231644643 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231644643) by changing a digit.

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 287 ways as a sum of consecutive naturals, for example, 11957664 + ... + 11957766.

It is an arithmetic number, because the mean of its divisors is an integer number (10403640).

Almost surely, 2^1231644645 is an apocalyptic number.

1231644645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1231644645 is an abundant number, since it is smaller than the sum of its proper divisors (1764603675).

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

1231644645 is a wasteful number, since it uses less digits than its factorization.

1231644645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185 (or 175 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 1231644645 is about 35094.7951269131. The cubic root of 1231644645 is about 1071.9186018637.

The spelling of 1231644645 in words is "one billion, two hundred thirty-one million, six hundred forty-four thousand, six hundred forty-five".