684921242 has 4 divisors (see below), whose sum is σ = 1027381866. Its totient is φ = 342460620.

The previous prime is 684921227. The next prime is 684921257. The reversal of 684921242 is 242129486.

It is a happy number.

It is a Cunningham number, because it is equal to 26171²+1.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (684921227) and next prime (684921257).

It can be written as a sum of positive squares in only one way, i.e., 684921241 + 1 = 26171^2 + 1^2 .

It is a junction number, because it is equal to n+sod(n) for n = 684921196 and 684921205.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171230309 + ... + 171230312.

Almost surely, 2^684921242 is an apocalyptic number.

684921242 is a deficient number, since it is larger than the sum of its proper divisors (342460624).

684921242 is a wasteful number, since it uses less digits than its factorization.

684921242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342460623.

The product of its digits is 55296, while the sum is 38.

The square root of 684921242 is about 26171.0000191051. Note that the first 4 decimals coincide. The cubic root of 684921242 is about 881.4821965008.

The spelling of 684921242 in words is "six hundred eighty-four million, nine hundred twenty-one thousand, two hundred forty-two".