1025577781 has 2 divisors, whose sum is σ = 1025577782. Its totient is φ = 1025577780.

The previous prime is 1025577767. The next prime is 1025577829. The reversal of 1025577781 is 1877755201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 981819556 + 43758225 = 31334^2 + 6615^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1025577781 is a prime.

It is a super-2 number, since 2×1025577781² = 2103619569761767922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1025577181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 512788890 + 512788891.

It is an arithmetic number, because the mean of its divisors is an integer number (512788891).

Almost surely, 2^1025577781 is an apocalyptic number.

It is an amenable number.

1025577781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1025577781 is an equidigital number, since it uses as much as digits as its factorization.

1025577781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 137200, while the sum is 43.

The square root of 1025577781 is about 32024.6433391537. The cubic root of 1025577781 is about 1008.4542512156.

The spelling of 1025577781 in words is "one billion, twenty-five million, five hundred seventy-seven thousand, seven hundred eighty-one".