221618745 has 24 divisors (see below), whose sum is σ = 387950472. Its totient is φ = 117024000.

The previous prime is 221618743. The next prime is 221618759. The reversal of 221618745 is 547816122.

221618745 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 140564736 + 81054009 = 11856^2 + 9003^2 .

It is not a de Polignac number, because 221618745 - 2¹ = 221618743 is a prime.

It is a super-2 number, since 2×221618745² = 98229736270750050, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (221618741) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19836 + ... + 28925.

It is an arithmetic number, because the mean of its divisors is an integer number (16164603).

Almost surely, 2^221618745 is an apocalyptic number.

It is an amenable number.

221618745 is a deficient number, since it is larger than the sum of its proper divisors (166331727).

221618745 is a wasteful number, since it uses less digits than its factorization.

221618745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48873 (or 48870 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 221618745 is about 14886.8648479121. The cubic root of 221618745 is about 605.1580717576.

The spelling of 221618745 in words is "two hundred twenty-one million, six hundred eighteen thousand, seven hundred forty-five".