947967821 has 4 divisors (see below), whose sum is σ = 1003730652. Its totient is φ = 892204992.

The previous prime is 947967749. The next prime is 947967829. The reversal of 947967821 is 128769749.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128769749 = 1879 ⋅68531.

It can be written as a sum of positive squares in 2 ways, for example, as 887205796 + 60762025 = 29786^2 + 7795^2 .

It is a cyclic number.

It is not a de Polignac number, because 947967821 - 2¹⁴ = 947951437 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 (947967829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27881390 + ... + 27881423.

It is an arithmetic number, because the mean of its divisors is an integer number (250932663).

Almost surely, 2^947967821 is an apocalyptic number.

It is an amenable number.

947967821 is a deficient number, since it is larger than the sum of its proper divisors (55762831).

947967821 is a wasteful number, since it uses less digits than its factorization.

947967821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55762830.

The product of its digits is 1524096, while the sum is 53.

The square root of 947967821 is about 30789.0860695799. The cubic root of 947967821 is about 982.3461146673.

The spelling of 947967821 in words is "nine hundred forty-seven million, nine hundred sixty-seven thousand, eight hundred twenty-one".