21867420 has 48 divisors (see below), whose sum is σ = 61494048. Its totient is φ = 5806080.

The previous prime is 21867403. The next prime is 21867427. The reversal of 21867420 is 2476812.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21867427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16212 + ... + 17508.

It is an arithmetic number, because the mean of its divisors is an integer number (1281126).

Almost surely, 2^21867420 is an apocalyptic number.

21867420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21867420 is an abundant number, since it is smaller than the sum of its proper divisors (39626628).

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

21867420 is a wasteful number, since it uses less digits than its factorization.

21867420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1590 (or 1588 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 21867420 is about 4676.2613271715. The cubic root of 21867420 is about 279.6399283135.

The spelling of 21867420 in words is "twenty-one million, eight hundred sixty-seven thousand, four hundred twenty".