1181401638 has 32 divisors (see below), whose sum is σ = 2569415904. Its totient is φ = 360617472.

The previous prime is 1181401631. The next prime is 1181401643. The reversal of 1181401638 is 8361041811.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1181401599 and 1181401608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1181401631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 152745 + ... + 160292.

It is an arithmetic number, because the mean of its divisors is an integer number (80294247).

Almost surely, 2^1181401638 is an apocalyptic number.

1181401638 is an abundant number, since it is smaller than the sum of its proper divisors (1388014266).

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

1181401638 is a wasteful number, since it uses less digits than its factorization.

1181401638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313096.

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 1181401638 is about 34371.5236496726. The cubic root of 1181401638 is about 1057.1400412409.

The spelling of 1181401638 in words is "one billion, one hundred eighty-one million, four hundred one thousand, six hundred thirty-eight".