21019854 has 16 divisors (see below), whose sum is σ = 44512848. Its totient is φ = 6594432.

The previous prime is 21019849. The next prime is 21019879. The reversal of 21019854 is 45891012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102937 + ... + 103140.

It is an arithmetic number, because the mean of its divisors is an integer number (2782053).

Almost surely, 2^21019854 is an apocalyptic number.

21019854 is an abundant number, since it is smaller than the sum of its proper divisors (23492994).

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

21019854 is a wasteful number, since it uses less digits than its factorization.

21019854 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206099.

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 21019854 is about 4584.7414321857. The cubic root of 21019854 is about 275.9793357770.

The spelling of 21019854 in words is "twenty-one million, nineteen thousand, eight hundred fifty-four".