243420157 has 4 divisors (see below), whose sum is σ = 249357276. Its totient is φ = 237483040.

The previous prime is 243420143. The next prime is 243420181. The reversal of 243420157 is 751024342.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 751024342 = 2 ⋅375512171.

It can be written as a sum of positive squares in 2 ways, for example, as 23609881 + 219810276 = 4859^2 + 14826^2 .

It is a cyclic number.

It is not a de Polignac number, because 243420157 - 2¹⁹ = 242895869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243420137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2968498 + ... + 2968579.

It is an arithmetic number, because the mean of its divisors is an integer number (62339319).

Almost surely, 2^243420157 is an apocalyptic number.

It is an amenable number.

243420157 is a deficient number, since it is larger than the sum of its proper divisors (5937119).

243420157 is an equidigital number, since it uses as much as digits as its factorization.

243420157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5937118.

The product of its (nonzero) digits is 6720, while the sum is 28.

The square root of 243420157 is about 15601.9279898351. The cubic root of 243420157 is about 624.3845948813.

Adding to 243420157 its reverse (751024342), we get a palindrome (994444499).

The spelling of 243420157 in words is "two hundred forty-three million, four hundred twenty thousand, one hundred fifty-seven".