221410256626661 has 4 divisors (see below), whose sum is σ = 222896231503500. Its totient is φ = 219924281749824.

The previous prime is 221410256626621. The next prime is 221410256626679. The reversal of 221410256626661 is 166626652014122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 54214210780900 + 167196045845761 = 7363030^2 + 12930431^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221410256626661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221410256626621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 742987438196 + ... + 742987438493.

It is an arithmetic number, because the mean of its divisors is an integer number (55724057875875).

Almost surely, 2^{221410256626661} is an apocalyptic number.

It is an amenable number.

221410256626661 is a deficient number, since it is larger than the sum of its proper divisors (1485974876839).

221410256626661 is a wasteful number, since it uses less digits than its factorization.

221410256626661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1485974876838.

The product of its (nonzero) digits is 2488320, while the sum is 50.

The spelling of 221410256626661 in words is "two hundred twenty-one trillion, four hundred ten billion, two hundred fifty-six million, six hundred twenty-six thousand, six hundred sixty-one".