242137821 has 4 divisors (see below), whose sum is σ = 322850432. Its totient is φ = 161425212.

The previous prime is 242137811. The next prime is 242137823. The reversal of 242137821 is 128731242.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 242137821 - 2⁶ = 242137757 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 (242137823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40356301 + ... + 40356306.

It is an arithmetic number, because the mean of its divisors is an integer number (80712608).

Almost surely, 2^242137821 is an apocalyptic number.

It is an amenable number.

242137821 is a deficient number, since it is larger than the sum of its proper divisors (80712611).

242137821 is an equidigital number, since it uses as much as digits as its factorization.

242137821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80712610.

The product of its digits is 5376, while the sum is 30.

The square root of 242137821 is about 15560.7782903041. The cubic root of 242137821 is about 623.2862457559.

The spelling of 242137821 in words is "two hundred forty-two million, one hundred thirty-seven thousand, eight hundred twenty-one".