149638721 has 4 divisors (see below), whose sum is σ = 149756100. Its totient is φ = 149521344.

The previous prime is 149638717. The next prime is 149638729. The reversal of 149638721 is 127836941.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 105349696 + 44289025 = 10264^2 + 6655^2 .

It is a cyclic number.

It is not a de Polignac number, because 149638721 - 2² = 149638717 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (149638729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56756 + ... + 59333.

It is an arithmetic number, because the mean of its divisors is an integer number (37439025).

Almost surely, 2^149638721 is an apocalyptic number.

It is an amenable number.

149638721 is a deficient number, since it is larger than the sum of its proper divisors (117379).

149638721 is a wasteful number, since it uses less digits than its factorization.

149638721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117378.

The product of its digits is 72576, while the sum is 41.

The square root of 149638721 is about 12232.6906688594. The cubic root of 149638721 is about 530.9023680775.

The spelling of 149638721 in words is "one hundred forty-nine million, six hundred thirty-eight thousand, seven hundred twenty-one".