220021551 has 6 divisors (see below), whose sum is σ = 317808920. Its totient is φ = 146681028.

The previous prime is 220021517. The next prime is 220021559. The reversal of 220021551 is 155120022.

It is not a de Polignac number, because 220021551 - 2²² = 215827247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220021559) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12223411 + ... + 12223428.

Almost surely, 2^220021551 is an apocalyptic number.

220021551 is a deficient number, since it is larger than the sum of its proper divisors (97787369).

220021551 is a wasteful number, since it uses less digits than its factorization.

220021551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24446845 (or 24446842 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 220021551 is about 14833.1234404626. The cubic root of 220021551 is about 603.7007850525.

Adding to 220021551 its reverse (155120022), we get a palindrome (375141573).

The spelling of 220021551 in words is "two hundred twenty million, twenty-one thousand, five hundred fifty-one".