154521821 has 2 divisors, whose sum is σ = 154521822. Its totient is φ = 154521820.

The previous prime is 154521817. The next prime is 154521839. The reversal of 154521821 is 128125451.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 82101721 + 72420100 = 9061^2 + 8510^2 .

It is a cyclic number.

It is not a de Polignac number, because 154521821 - 2² = 154521817 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (154521121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77260910 + 77260911.

It is an arithmetic number, because the mean of its divisors is an integer number (77260911).

Almost surely, 2^154521821 is an apocalyptic number.

It is an amenable number.

154521821 is a deficient number, since it is larger than the sum of its proper divisors (1).

154521821 is an equidigital number, since it uses as much as digits as its factorization.

154521821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3200, while the sum is 29.

The square root of 154521821 is about 12430.6806330144. The cubic root of 154521821 is about 536.6155735386.

The spelling of 154521821 in words is "one hundred fifty-four million, five hundred twenty-one thousand, eight hundred twenty-one".