1021651261 has 16 divisors (see below), whose sum is σ = 1140220800. Its totient is φ = 909715968.

The previous prime is 1021651247. The next prime is 1021651273. The reversal of 1021651261 is 1621561201.

It is a happy number.

It is not a de Polignac number, because 1021651261 - 2⁵ = 1021651229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021651201) 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 15 ways as a sum of consecutive naturals, for example, 306160 + ... + 309478.

It is an arithmetic number, because the mean of its divisors is an integer number (71263800).

Almost surely, 2^1021651261 is an apocalyptic number.

It is an amenable number.

1021651261 is a deficient number, since it is larger than the sum of its proper divisors (118569539).

1021651261 is a wasteful number, since it uses less digits than its factorization.

1021651261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4308.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 1021651261 is about 31963.2798848929. The cubic root of 1021651261 is about 1007.1656182726.

The spelling of 1021651261 in words is "one billion, twenty-one million, six hundred fifty-one thousand, two hundred sixty-one".