1291641791780 has 24 divisors (see below), whose sum is σ = 2712488546040. Its totient is φ = 516648948480.

The previous prime is 1291641791761. The next prime is 1291641791789. The reversal of 1291641791780 is 871971461921.

It can be written as a sum of positive squares in 4 ways, for example, as 17682616576 + 1273959175204 = 132976^2 + 1128698^2 .

It is a super-4 number, since 4×1291641791780⁴ (a number of 50 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (1291641791789) 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, 986816 + ... + 1886024.

It is an arithmetic number, because the mean of its divisors is an integer number (113020356085).

Almost surely, 2^{1291641791780} is an apocalyptic number.

1291641791780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1291641791780 is an abundant number, since it is smaller than the sum of its proper divisors (1420846754260).

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

1291641791780 is a wasteful number, since it uses less digits than its factorization.

1291641791780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 971039 (or 971037 counting only the distinct ones).

The product of its (nonzero) digits is 1524096, while the sum is 56.

The spelling of 1291641791780 in words is "one trillion, two hundred ninety-one billion, six hundred forty-one million, seven hundred ninety-one thousand, seven hundred eighty".