155277334721 has 4 divisors (see below), whose sum is σ = 157404421572. Its totient is φ = 153150247872.

The previous prime is 155277334699. The next prime is 155277334727. The reversal of 155277334721 is 127433772551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127433772551 = 29 ⋅4394268019.

It can be written as a sum of positive squares in 2 ways, for example, as 51025840321 + 104251494400 = 225889^2 + 322880^2 .

It is a cyclic number.

It is not a de Polignac number, because 155277334721 - 2²² = 155273140417 is a prime.

It is a super-2 number, since 2×155277334721² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155277334727) 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, 1063543316 + ... + 1063543461.

It is an arithmetic number, because the mean of its divisors is an integer number (39351105393).

Almost surely, 2^155277334721 is an apocalyptic number.

It is an amenable number.

155277334721 is a deficient number, since it is larger than the sum of its proper divisors (2127086851).

155277334721 is an equidigital number, since it uses as much as digits as its factorization.

155277334721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2127086850.

The product of its digits is 1234800, while the sum is 47.

The spelling of 155277334721 in words is "one hundred fifty-five billion, two hundred seventy-seven million, three hundred thirty-four thousand, seven hundred twenty-one".