2021031521 has 2 divisors, whose sum is σ = 2021031522. Its totient is φ = 2021031520.

The previous prime is 2021031517. The next prime is 2021031533. The reversal of 2021031521 is 1251301202.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1336633600 + 684397921 = 36560^2 + 26161^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021031521 - 2² = 2021031517 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2021031521.

It is not a weakly prime, because it can be changed into another prime (2021031821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010515760 + 1010515761.

It is an arithmetic number, because the mean of its divisors is an integer number (1010515761).

Almost surely, 2^2021031521 is an apocalyptic number.

It is an amenable number.

2021031521 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021031521 is an equidigital number, since it uses as much as digits as its factorization.

2021031521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 2021031521 is about 44955.8841643672. The cubic root of 2021031521 is about 1264.3220019729.

Adding to 2021031521 its reverse (1251301202), we get a palindrome (3272332723).

The spelling of 2021031521 in words is "two billion, twenty-one million, thirty-one thousand, five hundred twenty-one".