221656251406 has 16 divisors (see below), whose sum is σ = 358903677600. Its totient is φ = 102354010528.

The previous prime is 221656251361. The next prime is 221656251461. The reversal of 221656251406 is 604152656122.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 83078221 + ... + 83080888.

It is an arithmetic number, because the mean of its divisors is an integer number (22431479850).

Almost surely, 2^221656251406 is an apocalyptic number.

221656251406 is a deficient number, since it is larger than the sum of its proper divisors (137247426194).

221656251406 is a wasteful number, since it uses less digits than its factorization.

221656251406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166159163.

The product of its (nonzero) digits is 172800, while the sum is 40.

The spelling of 221656251406 in words is "two hundred twenty-one billion, six hundred fifty-six million, two hundred fifty-one thousand, four hundred six".