1281919863961 has 9 divisors (see below), whose sum is σ = 1409066102143. Its totient is φ = 1165370372320.

The previous prime is 1281919863877. The next prime is 1281919863971. The reversal of 1281919863961 is 1693689191821.

The square root of 1281919863961 is 1132219.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1255701777561 + 26218086400 = 1120581^2 + 161920^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1281919863961 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1281919863893 and 1281919863902.

It is not an unprimeable number, because it can be changed into a prime (1281919863971) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 12402945 + ... + 12505873.

Almost surely, 2^{1281919863961} is an apocalyptic number.

1281919863961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1281919863961 is the 1132219-th square number.

1281919863961 is the 566110-th centered octagonal number.

It is an amenable number.

1281919863961 is a deficient number, since it is larger than the sum of its proper divisors (127146238182).

1281919863961 is an frugal number, since it uses more digits than its factorization.

1281919863961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205880 (or 102940 counting only the distinct ones).

The product of its digits is 10077696, while the sum is 64.

Multiplying 1281919863961 by its sum of digits (64), we get a square (82042871293504 = 9057752²).

The spelling of 1281919863961 in words is "one trillion, two hundred eighty-one billion, nine hundred nineteen million, eight hundred sixty-three thousand, nine hundred sixty-one".