1551551234321 has 4 divisors (see below), whose sum is σ = 1692601346544. Its totient is φ = 1410501122100.

The previous prime is 1551551234297. The next prime is 1551551234347. The reversal of 1551551234321 is 1234321551551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1551551234321 - 2⁶ = 1551551234257 is a prime.

It is a super-2 number, since 2×1551551234321² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1551551234371) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70525056095 + ... + 70525056116.

It is an arithmetic number, because the mean of its divisors is an integer number (423150336636).

Almost surely, 2^{1551551234321} is an apocalyptic number.

1551551234321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1551551234321 is a deficient number, since it is larger than the sum of its proper divisors (141050112223).

1551551234321 is a wasteful number, since it uses less digits than its factorization.

1551551234321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141050112222.

The product of its digits is 90000, while the sum is 38.

Adding to 1551551234321 its reverse (1234321551551), we get a palindrome (2785872785872).

The spelling of 1551551234321 in words is "one trillion, five hundred fifty-one billion, five hundred fifty-one million, two hundred thirty-four thousand, three hundred twenty-one".