221029406 has 16 divisors (see below), whose sum is σ = 357548688. Its totient is φ = 101870400.

The previous prime is 221029397. The next prime is 221029423. The reversal of 221029406 is 604920122.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14201 + ... + 25371.

It is an arithmetic number, because the mean of its divisors is an integer number (22346793).

Almost surely, 2^221029406 is an apocalyptic number.

221029406 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

221029406 is a deficient number, since it is larger than the sum of its proper divisors (136519282).

221029406 is a wasteful number, since it uses less digits than its factorization.

221029406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11947.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 221029406 is about 14867.0577452299. The cubic root of 221029406 is about 604.6211739501.

Adding to 221029406 its reverse (604920122), we get a palindrome (825949528).

The spelling of 221029406 in words is "two hundred twenty-one million, twenty-nine thousand, four hundred six".