21678954 has 32 divisors (see below), whose sum is σ = 47540736. Its totient is φ = 6535920.

The previous prime is 21678953. The next prime is 21678959. The reversal of 21678954 is 45987612.

It is not an unprimeable number, because it can be changed into a prime (21678953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14259 + ... + 15705.

It is an arithmetic number, because the mean of its divisors is an integer number (1485648).

Almost surely, 2^21678954 is an apocalyptic number.

21678954 is an abundant number, since it is smaller than the sum of its proper divisors (25861782).

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

21678954 is a wasteful number, since it uses less digits than its factorization.

21678954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1690.

The product of its digits is 120960, while the sum is 42.

The square root of 21678954 is about 4656.0663655064. The cubic root of 21678954 is about 278.8342433411.

The spelling of 21678954 in words is "twenty-one million, six hundred seventy-eight thousand, nine hundred fifty-four".