1264397721615 has 288 divisors, whose sum is σ = 2809091638080. Its totient is φ = 542968344576.

The previous prime is 1264397721599. The next prime is 1264397721641. The reversal of 1264397721615 is 5161277934621.

1264397721615 is a `hidden beast` number, since 1 + 26 + 4 + 397 + 7 + 216 + 15 = 666.

It is not a de Polignac number, because 1264397721615 - 2⁴ = 1264397721599 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 63871159 + ... + 63890951.

It is an arithmetic number, because the mean of its divisors is an integer number (9753790410).

Almost surely, 2^{1264397721615} is an apocalyptic number.

1264397721615 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1264397721615 is an abundant number, since it is smaller than the sum of its proper divisors (1544693916465).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1264397721615 is a wasteful number, since it uses less digits than its factorization.

1264397721615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19893 (or 19874 counting only the distinct ones).

The product of its digits is 3810240, while the sum is 54.

The spelling of 1264397721615 in words is "one trillion, two hundred sixty-four billion, three hundred ninety-seven million, seven hundred twenty-one thousand, six hundred fifteen".