155046721 has 2 divisors, whose sum is σ = 155046722. Its totient is φ = 155046720.

The previous prime is 155046667. The next prime is 155046751. The reversal of 155046721 is 127640551.

155046721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 154256400 + 790321 = 12420^2 + 889^2 .

It is a cyclic number.

It is not a de Polignac number, because 155046721 - 2¹³ = 155038529 is a prime.

It is not a weakly prime, because it can be changed into another prime (155046751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77523360 + 77523361.

It is an arithmetic number, because the mean of its divisors is an integer number (77523361).

Almost surely, 2^155046721 is an apocalyptic number.

It is an amenable number.

155046721 is a deficient number, since it is larger than the sum of its proper divisors (1).

155046721 is an equidigital number, since it uses as much as digits as its factorization.

155046721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 155046721 is about 12451.7758171275. The cubic root of 155046721 is about 537.2225022255. Note that the first 3 decimals are identical.

The spelling of 155046721 in words is "one hundred fifty-five million, forty-six thousand, seven hundred twenty-one".