921890521 has 2 divisors, whose sum is σ = 921890522. Its totient is φ = 921890520.

The previous prime is 921890503. The next prime is 921890539. The reversal of 921890521 is 125098129.

It is the 12396-th star number.

It is a balanced prime because it is at equal distance from previous prime (921890503) and next prime (921890539).

It can be written as a sum of positive squares in only one way, i.e., 706974921 + 214915600 = 26589^2 + 14660^2 .

It is a cyclic number.

It is not a de Polignac number, because 921890521 - 2⁹ = 921890009 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (921890551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460945260 + 460945261.

It is an arithmetic number, because the mean of its divisors is an integer number (460945261).

Almost surely, 2^921890521 is an apocalyptic number.

It is an amenable number.

921890521 is a deficient number, since it is larger than the sum of its proper divisors (1).

921890521 is an equidigital number, since it uses as much as digits as its factorization.

921890521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 921890521 is about 30362.6500984351. The cubic root of 921890521 is about 973.2545659216.

The spelling of 921890521 in words is "nine hundred twenty-one million, eight hundred ninety thousand, five hundred twenty-one".