1215532978 has 16 divisors (see below), whose sum is σ = 1989590400. Its totient is φ = 552366000.

The previous prime is 1215532939. The next prime is 1215532979. The reversal of 1215532978 is 8792355121.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1215532979) 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, 148903 + ... + 156853.

It is an arithmetic number, because the mean of its divisors is an integer number (124349400).

Almost surely, 2^1215532978 is an apocalyptic number.

1215532978 is a deficient number, since it is larger than the sum of its proper divisors (774057422).

1215532978 is a wasteful number, since it uses less digits than its factorization.

1215532978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14913.

The product of its digits is 151200, while the sum is 43.

The square root of 1215532978 is about 34864.4945180624. The cubic root of 1215532978 is about 1067.2239970053.

The spelling of 1215532978 in words is "one billion, two hundred fifteen million, five hundred thirty-two thousand, nine hundred seventy-eight".