1215615551 has 8 divisors (see below), whose sum is σ = 1227733200. Its totient is φ = 1203512128.

The previous prime is 1215615539. The next prime is 1215615553. The reversal of 1215615551 is 1555165121.

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

It is a cyclic number.

It is not a de Polignac number, because 1215615551 - 2⁶ = 1215615487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1215615553) 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, 270515 + ... + 274971.

It is an arithmetic number, because the mean of its divisors is an integer number (153466650).

Almost surely, 2^1215615551 is an apocalyptic number.

1215615551 is a deficient number, since it is larger than the sum of its proper divisors (12117649).

1215615551 is a wasteful number, since it uses less digits than its factorization.

1215615551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7113.

The product of its digits is 7500, while the sum is 32.

The square root of 1215615551 is about 34865.6786969650. The cubic root of 1215615551 is about 1067.2481625067.

The spelling of 1215615551 in words is "one billion, two hundred fifteen million, six hundred fifteen thousand, five hundred fifty-one".