1021256025 has 24 divisors (see below), whose sum is σ = 1746703680. Its totient is φ = 525887040.

The previous prime is 1021255933. The next prime is 1021256029. The reversal of 1021256025 is 5206521201.

It is a happy number.

It is not a de Polignac number, because 1021256025 - 2⁹ = 1021255513 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1021255986 and 1021256004.

It is not an unprimeable number, because it can be changed into a prime (1021256029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 232597 + ... + 236946.

It is an arithmetic number, because the mean of its divisors is an integer number (72779320).

Almost surely, 2^1021256025 is an apocalyptic number.

1021256025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1021256025 is a deficient number, since it is larger than the sum of its proper divisors (725447655).

1021256025 is a wasteful number, since it uses less digits than its factorization.

1021256025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 469585 (or 469580 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 1021256025 is about 31957.0966297003. The cubic root of 1021256025 is about 1007.0357241595.

Adding to 1021256025 its reverse (5206521201), we get a palindrome (6227777226).

The spelling of 1021256025 in words is "one billion, twenty-one million, two hundred fifty-six thousand, twenty-five".