127649821 has 8 divisors (see below), whose sum is σ = 145555704. Its totient is φ = 110899200.

The previous prime is 127649803. The next prime is 127649827. The reversal of 127649821 is 128946721.

It can be written as a sum of positive squares in 4 ways, for example, as 57592921 + 70056900 = 7589^2 + 8370^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 127649821 - 2⁵ = 127649789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (127649827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 288580 + ... + 289021.

It is an arithmetic number, because the mean of its divisors is an integer number (18194463).

Almost surely, 2^127649821 is an apocalyptic number.

It is an amenable number.

127649821 is a deficient number, since it is larger than the sum of its proper divisors (17905883).

127649821 is a wasteful number, since it uses less digits than its factorization.

127649821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 577631.

The product of its digits is 48384, while the sum is 40.

The square root of 127649821 is about 11298.2220282662. Note that the first 3 decimals coincide. The cubic root of 127649821 is about 503.5084190776.

The spelling of 127649821 in words is "one hundred twenty-seven million, six hundred forty-nine thousand, eight hundred twenty-one".