155016421406621 has 2 divisors, whose sum is σ = 155016421406622. Its totient is φ = 155016421406620.

The previous prime is 155016421406611. The next prime is 155016421406629. The reversal of 155016421406621 is 126604124610551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79741953127225 + 75274468279396 = 8929835^2 + 8676086^2 .

It is a cyclic number.

It is not a de Polignac number, because 155016421406621 - 2²² = 155016417212317 is a prime.

It is a super-3 number, since 3×155016421406621³ (a number of 44 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155016421406629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77508210703310 + 77508210703311.

It is an arithmetic number, because the mean of its divisors is an integer number (77508210703311).

Almost surely, 2^{155016421406621} is an apocalyptic number.

It is an amenable number.

155016421406621 is a deficient number, since it is larger than the sum of its proper divisors (1).

155016421406621 is an equidigital number, since it uses as much as digits as its factorization.

155016421406621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 345600, while the sum is 44.

The spelling of 155016421406621 in words is "one hundred fifty-five trillion, sixteen billion, four hundred twenty-one million, four hundred six thousand, six hundred twenty-one".