133731421 has 2 divisors, whose sum is σ = 133731422. Its totient is φ = 133731420.

The previous prime is 133731379. The next prime is 133731439. The reversal of 133731421 is 124137331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 103327225 + 30404196 = 10165^2 + 5514^2 .

It is a cyclic number.

It is not a de Polignac number, because 133731421 - 2⁷ = 133731293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133731491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66865710 + 66865711.

It is an arithmetic number, because the mean of its divisors is an integer number (66865711).

Almost surely, 2^133731421 is an apocalyptic number.

It is an amenable number.

133731421 is a deficient number, since it is larger than the sum of its proper divisors (1).

133731421 is an equidigital number, since it uses as much as digits as its factorization.

133731421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1512, while the sum is 25.

The square root of 133731421 is about 11564.2302381092. The cubic root of 133731421 is about 511.3808803233.

Adding to 133731421 its reverse (124137331), we get a palindrome (257868752).

The spelling of 133731421 in words is "one hundred thirty-three million, seven hundred thirty-one thousand, four hundred twenty-one".