221204631 has 16 divisors (see below), whose sum is σ = 313372800. Its totient is φ = 138398688.

The previous prime is 221204609. The next prime is 221204657. The reversal of 221204631 is 136402122.

It is not a de Polignac number, because 221204631 - 2¹⁰ = 221203607 is a prime.

It is a super-2 number, since 2×221204631² = 97862977551692322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221204598 and 221204607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221204531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12036 + ... + 24233.

It is an arithmetic number, because the mean of its divisors is an integer number (19585800).

Almost surely, 2^221204631 is an apocalyptic number.

221204631 is a deficient number, since it is larger than the sum of its proper divisors (92168169).

221204631 is a wasteful number, since it uses less digits than its factorization.

221204631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36398.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 221204631 is about 14872.9496402025. The cubic root of 221204631 is about 604.7809064836.

Adding to 221204631 its reverse (136402122), we get a palindrome (357606753).

The spelling of 221204631 in words is "two hundred twenty-one million, two hundred four thousand, six hundred thirty-one".