1215216651 has 16 divisors (see below), whose sum is σ = 1768353408. Its totient is φ = 736176000.

The previous prime is 1215216643. The next prime is 1215216677. The reversal of 1215216651 is 1566125121.

It is not a de Polignac number, because 1215216651 - 2³ = 1215216643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1215216601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 85860 + ... + 99006.

It is an arithmetic number, because the mean of its divisors is an integer number (110522088).

Almost surely, 2^1215216651 is an apocalyptic number.

1215216651 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1215216651 is a deficient number, since it is larger than the sum of its proper divisors (553136757).

1215216651 is a wasteful number, since it uses less digits than its factorization.

1215216651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15962.

The product of its digits is 3600, while the sum is 30.

The square root of 1215216651 is about 34859.9577022119. The cubic root of 1215216651 is about 1067.1314118156.

The spelling of 1215216651 in words is "one billion, two hundred fifteen million, two hundred sixteen thousand, six hundred fifty-one".