221661372693 has 16 divisors (see below), whose sum is σ = 302394790656. Its totient is φ = 144362727360.

The previous prime is 221661372643. The next prime is 221661372731. The reversal of 221661372693 is 396273166122.

It is not a de Polignac number, because 221661372693 - 2¹⁷ = 221661241621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221661372643) 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, 1376646 + ... + 1529207.

It is an arithmetic number, because the mean of its divisors is an integer number (18899674416).

Almost surely, 2^221661372693 is an apocalyptic number.

It is an amenable number.

221661372693 is a deficient number, since it is larger than the sum of its proper divisors (80733417963).

221661372693 is a wasteful number, since it uses less digits than its factorization.

221661372693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2906444.

The product of its digits is 979776, while the sum is 48.

The spelling of 221661372693 in words is "two hundred twenty-one billion, six hundred sixty-one million, three hundred seventy-two thousand, six hundred ninety-three".