1221444551 has 8 divisors (see below), whose sum is σ = 1232235120. Its totient is φ = 1210701888.

The previous prime is 1221444527. The next prime is 1221444557. The reversal of 1221444551 is 1554441221.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1221444551 - 2⁶ = 1221444487 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 (1221444557) 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, 40235 + ... + 63731.

It is an arithmetic number, because the mean of its divisors is an integer number (154029390).

Almost surely, 2^1221444551 is an apocalyptic number.

1221444551 is a deficient number, since it is larger than the sum of its proper divisors (10790569).

1221444551 is a wasteful number, since it uses less digits than its factorization.

1221444551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23953.

The product of its digits is 6400, while the sum is 29.

The square root of 1221444551 is about 34949.1709629857. The cubic root of 1221444551 is about 1068.9512976010.

Adding to 1221444551 its reverse (1554441221), we get a palindrome (2775885772).

It can be divided in two parts, 12214 and 44551, that added together give a palindrome (56765).

The spelling of 1221444551 in words is "one billion, two hundred twenty-one million, four hundred forty-four thousand, five hundred fifty-one".