69921 has 12 divisors (see below), whose sum is σ = 107172. Its totient is φ = 43776.

The previous prime is 69911. The next prime is 69929. The reversal of 69921 is 12996.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 57600 + 12321 = 240^2 + 111^2 .

It is not a de Polignac number, because 69921 - 2⁶ = 69857 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

69921 is a lucky number.

It is a plaindrome in base 12.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 69921.

It is not an unprimeable number, because it can be changed into a prime (69929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 76 + ... + 381.

It is an arithmetic number, because the mean of its divisors is an integer number (8931).

2⁶⁹⁹²¹ is an apocalyptic number.

69921 is the 153-rd octagonal number.

It is an amenable number.

69921 is a deficient number, since it is larger than the sum of its proper divisors (37251).

69921 is a wasteful number, since it uses less digits than its factorization.

69921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 480 (or 477 counting only the distinct ones).

The product of its digits is 972, while the sum is 27.

The square root of 69921 is about 264.4257929930. The cubic root of 69921 is about 41.1973432792.

It can be divided in two parts, 69 and 921, that added together give a triangular number (990 = T₄₄).

The spelling of 69921 in words is "sixty-nine thousand, nine hundred twenty-one".