276640821 has 6 divisors (see below), whose sum is σ = 399592310. Its totient is φ = 184427208.

The previous prime is 276640811. The next prime is 276640877. The reversal of 276640821 is 128046672.

276640821 is a `hidden beast` number, since 2 + 7 + 6 + 640 + 8 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 173211921 + 103428900 = 13161^2 + 10170^2 .

It is not a de Polignac number, because 276640821 - 2²¹ = 274543669 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 (276640811) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 15368926 + ... + 15368943.

Almost surely, 2^276640821 is an apocalyptic number.

It is an amenable number.

276640821 is a deficient number, since it is larger than the sum of its proper divisors (122951489).

276640821 is a wasteful number, since it uses less digits than its factorization.

276640821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30737875 (or 30737872 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 276640821 is about 16632.5229896129. The cubic root of 276640821 is about 651.5865158134.

The spelling of 276640821 in words is "two hundred seventy-six million, six hundred forty thousand, eight hundred twenty-one".