1025786121721 has 3 divisors (see below), whose sum is σ = 1025787134533. Its totient is φ = 1025785108910.

The previous prime is 1025786121653. The next prime is 1025786121797. The reversal of 1025786121721 is 1271216875201.

It is a happy number.

The square root of 1025786121721 is 1012811.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 1025786121721 - 2⁹ = 1025786121209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1025786122721) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 506406 + ... + 1519216.

Almost surely, 2^{1025786121721} is an apocalyptic number.

1025786121721 is the 1012811-st square number.

1025786121721 is the 506406-th centered octagonal number.

It is an amenable number.

1025786121721 is a deficient number, since it is larger than the sum of its proper divisors (1012812).

1025786121721 is an frugal number, since it uses more digits than its factorization.

1025786121721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2025622 (or 1012811 counting only the distinct ones).

The product of its (nonzero) digits is 94080, while the sum is 43.

The spelling of 1025786121721 in words is "one trillion, twenty-five billion, seven hundred eighty-six million, one hundred twenty-one thousand, seven hundred twenty-one".