238978921 has 2 divisors, whose sum is σ = 238978922. Its totient is φ = 238978920.

The previous prime is 238978897. The next prime is 238978951. The reversal of 238978921 is 129879832.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 149108521 + 89870400 = 12211^2 + 9480^2 .

It is a cyclic number.

It is not a de Polignac number, because 238978921 - 2⁵ = 238978889 is a prime.

It is a super-2 number, since 2×238978921² = 114221849364648482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (238978951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 119489460 + 119489461.

It is an arithmetic number, because the mean of its divisors is an integer number (119489461).

Almost surely, 2^238978921 is an apocalyptic number.

It is an amenable number.

238978921 is a deficient number, since it is larger than the sum of its proper divisors (1).

238978921 is an equidigital number, since it uses as much as digits as its factorization.

238978921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 49.

The square root of 238978921 is about 15458.9430751264. The cubic root of 238978921 is about 620.5639345295.

The spelling of 238978921 in words is "two hundred thirty-eight million, nine hundred seventy-eight thousand, nine hundred twenty-one".