1213638987 has 8 divisors (see below), whose sum is σ = 1765293120. Its totient is φ = 735538760.

The previous prime is 1213638971. The next prime is 1213639019. The reversal of 1213638987 is 7898363121.

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

It is not a de Polignac number, because 1213638987 - 2⁴ = 1213638971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1213638917) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18388437 + ... + 18388502.

It is an arithmetic number, because the mean of its divisors is an integer number (220661640).

Almost surely, 2^1213638987 is an apocalyptic number.

1213638987 is a deficient number, since it is larger than the sum of its proper divisors (551654133).

1213638987 is a wasteful number, since it uses less digits than its factorization.

1213638987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36776953.

The product of its digits is 435456, while the sum is 48.

The square root of 1213638987 is about 34837.3217541188. The cubic root of 1213638987 is about 1066.6694080767.

The spelling of 1213638987 in words is "one billion, two hundred thirteen million, six hundred thirty-eight thousand, nine hundred eighty-seven".