30638975221 has 8 divisors (see below), whose sum is σ = 30800608344. Its totient is φ = 30477404160.

The previous prime is 30638975153. The next prime is 30638975243. The reversal of 30638975221 is 12257983603.

30638975221 = T₁₄₂₉₁₈ + T₁₄₂₉₁₉ + T₁₄₂₉₂₀.

It can be written as a sum of positive squares in 4 ways, for example, as 3616218225 + 27022756996 = 60135^2 + 164386^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 6-Lehmer number, since φ(30638975221) divides (30638975221-1)⁶.

It is a cyclic number.

It is not a de Polignac number, because 30638975221 - 2¹⁷ = 30638844149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30638975021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1239301 + ... + 1263781.

It is an arithmetic number, because the mean of its divisors is an integer number (3850076043).

Almost surely, 2^30638975221 is an apocalyptic number.

30638975221 is the 142920-th centered triangular number.

It is an amenable number.

30638975221 is a deficient number, since it is larger than the sum of its proper divisors (161633123).

30638975221 is a wasteful number, since it uses less digits than its factorization.

30638975221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31031.

The product of its (nonzero) digits is 544320, while the sum is 46.

The spelling of 30638975221 in words is "thirty billion, six hundred thirty-eight million, nine hundred seventy-five thousand, two hundred twenty-one".