947877821 has 6 divisors (see below), whose sum is σ = 1041882366. Its totient is φ = 861707000.

The previous prime is 947877781. The next prime is 947877851. The reversal of 947877821 is 128778749.

It can be written as a sum of positive squares in only one way, i.e., 928420900 + 19456921 = 30470^2 + 4411^2 .

It is not a de Polignac number, because 947877821 - 2¹⁴ = 947861437 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 (947877851) 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, 3916730 + ... + 3916971.

It is an arithmetic number, because the mean of its divisors is an integer number (173647061).

Almost surely, 2^947877821 is an apocalyptic number.

It is an amenable number.

947877821 is a deficient number, since it is larger than the sum of its proper divisors (94004545).

947877821 is a wasteful number, since it uses less digits than its factorization.

947877821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7833723 (or 7833712 counting only the distinct ones).

The product of its digits is 1580544, while the sum is 53.

The square root of 947877821 is about 30787.6244780269. The cubic root of 947877821 is about 982.3150257258.

The spelling of 947877821 in words is "nine hundred forty-seven million, eight hundred seventy-seven thousand, eight hundred twenty-one".