1285777361 has 4 divisors (see below), whose sum is σ = 1402666224. Its totient is φ = 1168888500.

The previous prime is 1285777351. The next prime is 1285777373. The reversal of 1285777361 is 1637775821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1637775821 = 11 ⋅148888711.

It is a cyclic number.

It is not a de Polignac number, because 1285777361 - 2²² = 1281583057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1285777351) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58444415 + ... + 58444436.

It is an arithmetic number, because the mean of its divisors is an integer number (350666556).

Almost surely, 2^1285777361 is an apocalyptic number.

1285777361 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1285777361 is a deficient number, since it is larger than the sum of its proper divisors (116888863).

1285777361 is a wasteful number, since it uses less digits than its factorization.

1285777361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116888862.

The product of its digits is 493920, while the sum is 47.

The square root of 1285777361 is about 35857.7378120818. The cubic root of 1285777361 is about 1087.3981544823.

The spelling of 1285777361 in words is "one billion, two hundred eighty-five million, seven hundred seventy-seven thousand, three hundred sixty-one".