1216380251 has 16 divisors (see below), whose sum is σ = 1269777600. Its totient is φ = 1164334080.

The previous prime is 1216380233. The next prime is 1216380271. The reversal of 1216380251 is 1520836121.

It is a cyclic number.

It is not a de Polignac number, because 1216380251 - 2¹⁸ = 1216118107 is a prime.

It is a super-3 number, since 3×1216380251³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216380211) 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, 475925 + ... + 478473.

It is an arithmetic number, because the mean of its divisors is an integer number (79361100).

Almost surely, 2^1216380251 is an apocalyptic number.

1216380251 is a deficient number, since it is larger than the sum of its proper divisors (53397349).

1216380251 is a wasteful number, since it uses less digits than its factorization.

1216380251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2806.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 1216380251 is about 34876.6433447945. The cubic root of 1216380251 is about 1067.4719047355.

The spelling of 1216380251 in words is "one billion, two hundred sixteen million, three hundred eighty thousand, two hundred fifty-one".