133617821 has 2 divisors, whose sum is σ = 133617822. Its totient is φ = 133617820.

The previous prime is 133617797. The next prime is 133617839. The reversal of 133617821 is 128716331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75933796 + 57684025 = 8714^2 + 7595^2 .

It is an emirp because it is prime and its reverse (128716331) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 133617821 - 2¹⁴ = 133601437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133617721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66808910 + 66808911.

It is an arithmetic number, because the mean of its divisors is an integer number (66808911).

Almost surely, 2^133617821 is an apocalyptic number.

It is an amenable number.

133617821 is a deficient number, since it is larger than the sum of its proper divisors (1).

133617821 is an equidigital number, since it uses as much as digits as its factorization.

133617821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 32.

The square root of 133617821 is about 11559.3174971535. The cubic root of 133617821 is about 511.2360394559.

The spelling of 133617821 in words is "one hundred thirty-three million, six hundred seventeen thousand, eight hundred twenty-one".