1421215551 has 30 divisors (see below), whose sum is σ = 2469677760. Its totient is φ = 812120904.

The previous prime is 1421215531. The next prime is 1421215559. The reversal of 1421215551 is 1555121241.

It is a happy number.

It is not a de Polignac number, because 1421215551 - 2⁵ = 1421215519 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1421215559) 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 29 ways as a sum of consecutive naturals, for example, 175071 + ... + 183008.

It is an arithmetic number, because the mean of its divisors is an integer number (82322592).

Almost surely, 2^1421215551 is an apocalyptic number.

1421215551 is a deficient number, since it is larger than the sum of its proper divisors (1048462209).

1421215551 is an equidigital number, since it uses as much as digits as its factorization.

1421215551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358105 (or 358089 counting only the distinct ones).

The product of its digits is 2000, while the sum is 27.

The square root of 1421215551 is about 37699.0125998016. The cubic root of 1421215551 is about 1124.3114933825.

Adding to 1421215551 its reverse (1555121241), we get a palindrome (2976336792).

The spelling of 1421215551 in words is "one billion, four hundred twenty-one million, two hundred fifteen thousand, five hundred fifty-one".