971221428 has 36 divisors (see below), whose sum is σ = 2545961600. Its totient is φ = 323740152.

The previous prime is 971221421. The next prime is 971221463. The reversal of 971221428 is 824122179.

971221428 is a `hidden beast` number, since 9 + 7 + 1 + 221 + 428 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 971221392 and 971221401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (971221421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 498628 + ... + 500571.

Almost surely, 2^971221428 is an apocalyptic number.

It is an amenable number.

971221428 is an abundant number, since it is smaller than the sum of its proper divisors (1574740172).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

971221428 is a wasteful number, since it uses less digits than its factorization.

971221428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 999218 (or 999204 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 971221428 is about 31164.4256805737. The cubic root of 971221428 is about 990.3136196470.

The spelling of 971221428 in words is "nine hundred seventy-one million, two hundred twenty-one thousand, four hundred twenty-eight".