129991213 has 4 divisors (see below), whose sum is σ = 141808608. Its totient is φ = 118173820.

The previous prime is 129991207. The next prime is 129991223. The reversal of 129991213 is 312199921.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 312199921 = 11 ⋅28381811.

It is a cyclic number.

It is not a de Polignac number, because 129991213 - 2⁹ = 129990701 is a prime.

It is a super-2 number, since 2×129991213² = 33795430914422738, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129991223) 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, 5908681 + ... + 5908702.

It is an arithmetic number, because the mean of its divisors is an integer number (35452152).

Almost surely, 2^129991213 is an apocalyptic number.

It is an amenable number.

129991213 is a deficient number, since it is larger than the sum of its proper divisors (11817395).

129991213 is a wasteful number, since it uses less digits than its factorization.

129991213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11817394.

The product of its digits is 8748, while the sum is 37.

The square root of 129991213 is about 11401.3689090389. The cubic root of 129991213 is about 506.5682880226.

The spelling of 129991213 in words is "one hundred twenty-nine million, nine hundred ninety-one thousand, two hundred thirteen".