155147821 has 2 divisors, whose sum is σ = 155147822. Its totient is φ = 155147820.

The previous prime is 155147809. The next prime is 155147887. The reversal of 155147821 is 128741551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 109098025 + 46049796 = 10445^2 + 6786^2 .

It is a cyclic number.

It is not a de Polignac number, because 155147821 - 2⁵ = 155147789 is a prime.

It is a super-2 number, since 2×155147821² = 48141692722096082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155147921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77573910 + 77573911.

It is an arithmetic number, because the mean of its divisors is an integer number (77573911).

Almost surely, 2^155147821 is an apocalyptic number.

It is an amenable number.

155147821 is a deficient number, since it is larger than the sum of its proper divisors (1).

155147821 is an equidigital number, since it uses as much as digits as its factorization.

155147821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11200, while the sum is 34.

The square root of 155147821 is about 12455.8348174661. The cubic root of 155147821 is about 537.3392442280.

The spelling of 155147821 in words is "one hundred fifty-five million, one hundred forty-seven thousand, eight hundred twenty-one".