220121551 has 4 divisors (see below), whose sum is σ = 237053992. Its totient is φ = 203189112.

The previous prime is 220121549. The next prime is 220121563. The reversal of 220121551 is 155121022.

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

It is a cyclic number.

It is not a de Polignac number, because 220121551 - 2¹ = 220121549 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 (220121581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8466201 + ... + 8466226.

It is an arithmetic number, because the mean of its divisors is an integer number (59263498).

Almost surely, 2^220121551 is an apocalyptic number.

220121551 is a deficient number, since it is larger than the sum of its proper divisors (16932441).

220121551 is a wasteful number, since it uses less digits than its factorization.

220121551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16932440.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 220121551 is about 14836.4938917522. The cubic root of 220121551 is about 603.7922320562.

Adding to 220121551 its reverse (155121022), we get a palindrome (375242573).

It can be divided in two parts, 220 and 121551, that added together give a triangular number (121771 = T₄₉₃).

The spelling of 220121551 in words is "two hundred twenty million, one hundred twenty-one thousand, five hundred fifty-one".