209493457 has 2 divisors, whose sum is σ = 209493458. Its totient is φ = 209493456.

The previous prime is 209493437. The next prime is 209493461. The reversal of 209493457 is 754394902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 170668096 + 38825361 = 13064^2 + 6231^2 .

It is a cyclic number.

It is not a de Polignac number, because 209493457 - 2²⁷ = 75275729 is a prime.

It is not a weakly prime, because it can be changed into another prime (209493437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104746728 + 104746729.

It is an arithmetic number, because the mean of its divisors is an integer number (104746729).

Almost surely, 2^209493457 is an apocalyptic number.

It is an amenable number.

209493457 is a deficient number, since it is larger than the sum of its proper divisors (1).

209493457 is an equidigital number, since it uses as much as digits as its factorization.

209493457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 272160, while the sum is 43.

The square root of 209493457 is about 14473.8888001808. Note that the first 4 decimals coincide. The cubic root of 209493457 is about 593.9138974760.

The spelling of 209493457 in words is "two hundred nine million, four hundred ninety-three thousand, four hundred fifty-seven".