157940221 has 2 divisors, whose sum is σ = 157940222. Its totient is φ = 157940220.

The previous prime is 157940203. The next prime is 157940231. The reversal of 157940221 is 122049751.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 153884025 + 4056196 = 12405^2 + 2014^2 .

It is an emirp because it is prime and its reverse (122049751) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 157940221 - 2⁷ = 157940093 is a prime.

It is a super-2 number, since 2×157940221² = 49890226819057682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157940231) 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 as a sum of consecutive naturals, namely, 78970110 + 78970111.

It is an arithmetic number, because the mean of its divisors is an integer number (78970111).

Almost surely, 2^157940221 is an apocalyptic number.

It is an amenable number.

157940221 is a deficient number, since it is larger than the sum of its proper divisors (1).

157940221 is an equidigital number, since it uses as much as digits as its factorization.

157940221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 157940221 is about 12567.4269840728. The cubic root of 157940221 is about 540.5438291312.

Adding to 157940221 its reverse (122049751), we get a palindrome (279989972).

The spelling of 157940221 in words is "one hundred fifty-seven million, nine hundred forty thousand, two hundred twenty-one".