1264397405820 has 192 divisors, whose sum is σ = 3649681881216. Its totient is φ = 326828113920.

The previous prime is 1264397405809. The next prime is 1264397405839. The reversal of 1264397405820 is 285047934621.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1042371534 + ... + 1042372746.

It is an arithmetic number, because the mean of its divisors is an integer number (19008759798).

It is a 1-persistent number, because it is pandigital, but 2⋅1264397405820 = 2528794811640 is not.

Almost surely, 2^{1264397405820} is an apocalyptic number.

1264397405820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1264397405820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1824840940608).

1264397405820 is an abundant number, since it is smaller than the sum of its proper divisors (2385284475396).

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

1264397405820 is a wasteful number, since it uses less digits than its factorization.

1264397405820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2640 (or 2638 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 51.

The spelling of 1264397405820 in words is "one trillion, two hundred sixty-four billion, three hundred ninety-seven million, four hundred five thousand, eight hundred twenty".