1243055921 has 2 divisors, whose sum is σ = 1243055922. Its totient is φ = 1243055920.

The previous prime is 1243055909. The next prime is 1243055941. The reversal of 1243055921 is 1295503421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1236295921 + 6760000 = 35161^2 + 2600^2 .

It is a cyclic number.

It is not a de Polignac number, because 1243055921 - 2¹⁴ = 1243039537 is a prime.

It is not a weakly prime, because it can be changed into another prime (1243055941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621527960 + 621527961.

It is an arithmetic number, because the mean of its divisors is an integer number (621527961).

Almost surely, 2^1243055921 is an apocalyptic number.

It is an amenable number.

1243055921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1243055921 is an equidigital number, since it uses as much as digits as its factorization.

1243055921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 1243055921 is about 35256.9981847576. The cubic root of 1243055921 is about 1075.2188978430.

The spelling of 1243055921 in words is "one billion, two hundred forty-three million, fifty-five thousand, nine hundred twenty-one".