21421700 has 36 divisors (see below), whose sum is σ = 49223412. Its totient is φ = 8064000.

The previous prime is 21421693. The next prime is 21421703. The reversal of 21421700 is 712412.

It can be written as a sum of positive squares in 6 ways, for example, as 114244 + 21307456 = 338^2 + 4616^2 .

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421703) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4601 + ... + 8000.

It is an arithmetic number, because the mean of its divisors is an integer number (1367317).

Almost surely, 2^21421700 is an apocalyptic number.

21421700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21421700 is an abundant number, since it is smaller than the sum of its proper divisors (27801712).

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

21421700 is a wasteful number, since it uses less digits than its factorization.

21421700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12632 (or 12625 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 21421700 is about 4628.3582402403. The cubic root of 21421700 is about 277.7269198743.

The spelling of 21421700 in words is "twenty-one million, four hundred twenty-one thousand, seven hundred".