2155434435421 has 2 divisors, whose sum is σ = 2155434435422. Its totient is φ = 2155434435420.

The previous prime is 2155434435367. The next prime is 2155434435463. The reversal of 2155434435421 is 1245344345512.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1167674748100 + 987759687321 = 1080590^2 + 993861^2 .

It is a cyclic number.

It is not a de Polignac number, because 2155434435421 - 2³⁷ = 2017995481949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2155434439421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1077717217710 + 1077717217711.

It is an arithmetic number, because the mean of its divisors is an integer number (1077717217711).

Almost surely, 2^{2155434435421} is an apocalyptic number.

It is an amenable number.

2155434435421 is a deficient number, since it is larger than the sum of its proper divisors (1).

2155434435421 is an equidigital number, since it uses as much as digits as its factorization.

2155434435421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152000, while the sum is 43.

The spelling of 2155434435421 in words is "two trillion, one hundred fifty-five billion, four hundred thirty-four million, four hundred thirty-five thousand, four hundred twenty-one".