1020784894921 has 27 divisors (see below), whose sum is σ = 1144249652917. Its totient is φ = 909951716960.

The previous prime is 1020784894903. The next prime is 1020784894933. The reversal of 1020784894921 is 1294984870201.

The square root of 1020784894921 is 1010339.

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

It can be written as a sum of positive squares in 4 ways, for example, as 30202616521 + 990582278400 = 173789^2 + 995280^2 .

It is not a de Polignac number, because 1020784894921 - 2⁷ = 1020784894793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1020784894951) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 589026771 + ... + 589028503.

Almost surely, 2^{1020784894921} is an apocalyptic number.

1020784894921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1020784894921 is the 1010339-th square number.

1020784894921 is the 505170-th centered octagonal number.

It is an amenable number.

1020784894921 is a deficient number, since it is larger than the sum of its proper divisors (123464757996).

1020784894921 is an frugal number, since it uses more digits than its factorization.

1020784894921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3594 (or 1797 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 55.

The spelling of 1020784894921 in words is "one trillion, twenty billion, seven hundred eighty-four million, eight hundred ninety-four thousand, nine hundred twenty-one".