1221054551 has 8 divisors (see below), whose sum is σ = 1286585520. Its totient is φ = 1155650112.

The previous prime is 1221054539. The next prime is 1221054557. The reversal of 1221054551 is 1554501221.

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 1221054551 - 2²⁶ = 1153945687 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221054551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221054557) 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, 11480 + ... + 50733.

It is an arithmetic number, because the mean of its divisors is an integer number (160823190).

Almost surely, 2^1221054551 is an apocalyptic number.

1221054551 is a deficient number, since it is larger than the sum of its proper divisors (65530969).

1221054551 is a wasteful number, since it uses less digits than its factorization.

1221054551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63265.

The product of its (nonzero) digits is 2000, while the sum is 26.

The square root of 1221054551 is about 34943.5909860449. The cubic root of 1221054551 is about 1068.8375155539.

Adding to 1221054551 its reverse (1554501221), we get a palindrome (2775555772).

The spelling of 1221054551 in words is "one billion, two hundred twenty-one million, fifty-four thousand, five hundred fifty-one".