149220821 has 2 divisors, whose sum is σ = 149220822. Its totient is φ = 149220820.

The previous prime is 149220779. The next prime is 149220881. The reversal of 149220821 is 128022941.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 116856100 + 32364721 = 10810^2 + 5689^2 .

It is a cyclic number.

It is not a de Polignac number, because 149220821 - 2¹⁴ = 149204437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (149220881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 74610410 + 74610411.

It is an arithmetic number, because the mean of its divisors is an integer number (74610411).

Almost surely, 2^149220821 is an apocalyptic number.

It is an amenable number.

149220821 is a deficient number, since it is larger than the sum of its proper divisors (1).

149220821 is an equidigital number, since it uses as much as digits as its factorization.

149220821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 149220821 is about 12215.5974475258. The cubic root of 149220821 is about 530.4076856084.

The spelling of 149220821 in words is "one hundred forty-nine million, two hundred twenty thousand, eight hundred twenty-one".