221821856404 has 12 divisors (see below), whose sum is σ = 392031697428. Its totient is φ = 109812800000.

The previous prime is 221821856371. The next prime is 221821856411. The reversal of 221821856404 is 404658128122.

It can be written as a sum of positive squares in 2 ways, for example, as 208492692100 + 13329164304 = 456610^2 + 115452^2 .

It is a super-2 number, since 2×221821856404² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 274531597 + ... + 274532404.

It is an arithmetic number, because the mean of its divisors is an integer number (32669308119).

Almost surely, 2^221821856404 is an apocalyptic number.

It is an amenable number.

221821856404 is a deficient number, since it is larger than the sum of its proper divisors (170209841024).

221821856404 is a wasteful number, since it uses less digits than its factorization.

221821856404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549064106 (or 549064104 counting only the distinct ones).

The product of its (nonzero) digits is 245760, while the sum is 43.

The spelling of 221821856404 in words is "two hundred twenty-one billion, eight hundred twenty-one million, eight hundred fifty-six thousand, four hundred four".