1251421000155 has 24 divisors (see below), whose sum is σ = 2172634030320. Its totient is φ = 666346288320.

The previous prime is 1251421000139. The next prime is 1251421000157. The reversal of 1251421000155 is 5510001241521.

It is a happy number.

It is not a de Polignac number, because 1251421000155 - 2⁴ = 1251421000139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1251421000157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22435276 + ... + 22490985.

It is an arithmetic number, because the mean of its divisors is an integer number (90526417930).

Almost surely, 2^{1251421000155} is an apocalyptic number.

1251421000155 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1251421000155 is a deficient number, since it is larger than the sum of its proper divisors (921213030165).

1251421000155 is a wasteful number, since it uses less digits than its factorization.

1251421000155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44926891 (or 44926888 counting only the distinct ones).

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

Adding to 1251421000155 its reverse (5510001241521), we get a palindrome (6761422241676).

The spelling of 1251421000155 in words is "one trillion, two hundred fifty-one billion, four hundred twenty-one million, one hundred fifty-five", and thus it is an aban number.