133902721 has 4 divisors (see below), whose sum is σ = 133936132. Its totient is φ = 133869312.

The previous prime is 133902719. The next prime is 133902737. The reversal of 133902721 is 127209331.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127209331 = 557 ⋅228383.

It can be written as a sum of positive squares in 2 ways, for example, as 72437121 + 61465600 = 8511^2 + 7840^2 .

It is a cyclic number.

It is not a de Polignac number, because 133902721 - 2¹ = 133902719 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 133902721.

It is not an unprimeable number, because it can be changed into a prime (133902701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9720 + ... + 19033.

It is an arithmetic number, because the mean of its divisors is an integer number (33484033).

Almost surely, 2^133902721 is an apocalyptic number.

It is an amenable number.

133902721 is a deficient number, since it is larger than the sum of its proper divisors (33411).

133902721 is an equidigital number, since it uses as much as digits as its factorization.

133902721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33410.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 133902721 is about 11571.6343270949. The cubic root of 133902721 is about 511.5991341136.

The spelling of 133902721 in words is "one hundred thirty-three million, nine hundred two thousand, seven hundred twenty-one".