1213640981 has 8 divisors (see below), whose sum is σ = 1434846720. Its totient is φ = 1004392368.

The previous prime is 1213640969. The next prime is 1213640993. The reversal of 1213640981 is 1890463121.

It is an interprime number because it is at equal distance from previous prime (1213640969) and next prime (1213640993).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1213640981 - 2²² = 1209446677 is a prime.

It is a super-2 number, since 2×1213640981² = 2945848861525284722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213640951) 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 7 ways as a sum of consecutive naturals, for example, 2989061 + ... + 2989466.

It is an arithmetic number, because the mean of its divisors is an integer number (179355840).

Almost surely, 2^1213640981 is an apocalyptic number.

It is an amenable number.

1213640981 is a deficient number, since it is larger than the sum of its proper divisors (221205739).

1213640981 is an equidigital number, since it uses as much as digits as its factorization.

1213640981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5978563.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 1213640981 is about 34837.3503728398. The cubic root of 1213640981 is about 1066.6699922531.

The spelling of 1213640981 in words is "one billion, two hundred thirteen million, six hundred forty thousand, nine hundred eighty-one".