155721164429 has 2 divisors, whose sum is σ = 155721164430. Its totient is φ = 155721164428.

The previous prime is 155721164419. The next prime is 155721164437. The reversal of 155721164429 is 924461127551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 140923658404 + 14797506025 = 375398^2 + 121645^2 .

It is a cyclic number.

It is not a de Polignac number, because 155721164429 - 2¹⁶ = 155721098893 is a prime.

It is a super-2 number, since 2×155721164429² (a number of 23 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155721164419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77860582214 + 77860582215.

It is an arithmetic number, because the mean of its divisors is an integer number (77860582215).

Almost surely, 2^155721164429 is an apocalyptic number.

It is an amenable number.

155721164429 is a deficient number, since it is larger than the sum of its proper divisors (1).

155721164429 is an equidigital number, since it uses as much as digits as its factorization.

155721164429 is an evil number, because the sum of its binary digits is even.

The product of its digits is 604800, while the sum is 47.

The spelling of 155721164429 in words is "one hundred fifty-five billion, seven hundred twenty-one million, one hundred sixty-four thousand, four hundred twenty-nine".