21423700 has 18 divisors (see below), whose sum is σ = 46489646. Its totient is φ = 8569440.

The previous prime is 21423679. The next prime is 21423709. The reversal of 21423700 is 732412.

It can be written as a sum of positive squares in 3 ways, for example, as 1227664 + 20196036 = 1108^2 + 4494^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423709) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 107019 + ... + 107218.

Almost surely, 2^21423700 is an apocalyptic number.

21423700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21423700 is an abundant number, since it is smaller than the sum of its proper divisors (25065946).

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

21423700 is a wasteful number, since it uses less digits than its factorization.

21423700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214251 (or 214244 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 19.

The square root of 21423700 is about 4628.5742945317. The cubic root of 21423700 is about 277.7355627699.

The spelling of 21423700 in words is "twenty-one million, four hundred twenty-three thousand, seven hundred".