43123090921 has 3 divisors (see below), whose sum is σ = 43123298583. Its totient is φ = 43122883260.

The previous prime is 43123090877. The next prime is 43123090939. The reversal of 43123090921 is 12909032134.

The square root of 43123090921 is 207661.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 6832840921 + 36290250000 = 82661^2 + 190500^2 .

It is not a de Polignac number, because 43123090921 - 2¹³ = 43123082729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43123090951) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 103831 + ... + 311491.

It is an arithmetic number, because the mean of its divisors is an integer number (14374432861).

Almost surely, 2^43123090921 is an apocalyptic number.

43123090921 is the 207661-st square number.

43123090921 is the 103831-st centered octagonal number.

It is an amenable number.

43123090921 is a deficient number, since it is larger than the sum of its proper divisors (207662).

43123090921 is an frugal number, since it uses more digits than its factorization.

43123090921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415322 (or 207661 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 34.

Multiplying 43123090921 by its product of nonzero digits (11664), we get a square (502987732502544 = 22427388²).

The spelling of 43123090921 in words is "forty-three billion, one hundred twenty-three million, ninety thousand, nine hundred twenty-one".