221944537 has 8 divisors (see below), whose sum is σ = 241352136. Its totient is φ = 203242752.

The previous prime is 221944517. The next prime is 221944559. The reversal of 221944537 is 735449122.

It can be written as a sum of positive squares in 4 ways, for example, as 142181776 + 79762761 = 11924^2 + 8931^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 221944537 - 2⁷ = 221944409 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221944496 and 221944505.

It is not an unprimeable number, because it can be changed into a prime (221944507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 175798 + ... + 177055.

It is an arithmetic number, because the mean of its divisors is an integer number (30169017).

Almost surely, 2^221944537 is an apocalyptic number.

It is an amenable number.

221944537 is a deficient number, since it is larger than the sum of its proper divisors (19407599).

221944537 is a wasteful number, since it uses less digits than its factorization.

221944537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352907.

The product of its digits is 60480, while the sum is 37.

The square root of 221944537 is about 14897.8030930738. The cubic root of 221944537 is about 605.4544653492.

The spelling of 221944537 in words is "two hundred twenty-one million, nine hundred forty-four thousand, five hundred thirty-seven".