69420821 has 4 divisors (see below), whose sum is σ = 69454092. Its totient is φ = 69387552.

The previous prime is 69420817. The next prime is 69420829. The reversal of 69420821 is 12802496.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 51051025 + 18369796 = 7145^2 + 4286^2 .

It is a cyclic number.

It is not a de Polignac number, because 69420821 - 2² = 69420817 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (69420829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13280 + ... + 17753.

It is an arithmetic number, because the mean of its divisors is an integer number (17363523).

Almost surely, 2^69420821 is an apocalyptic number.

It is an amenable number.

69420821 is a deficient number, since it is larger than the sum of its proper divisors (33271).

69420821 is a wasteful number, since it uses less digits than its factorization.

69420821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33270.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 69420821 is about 8331.9158061037. The cubic root of 69420821 is about 410.9887320966.

The spelling of 69420821 in words is "sixty-nine million, four hundred twenty thousand, eight hundred twenty-one".