21730700 has 18 divisors (see below), whose sum is σ = 47155836. Its totient is φ = 8692240.

The previous prime is 21730693. The next prime is 21730727. The reversal of 21730700 is 703712.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 108554 + ... + 108753.

Almost surely, 2^21730700 is an apocalyptic number.

21730700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21730700 is an abundant number, since it is smaller than the sum of its proper divisors (25425136).

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

21730700 is a wasteful number, since it uses less digits than its factorization.

21730700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217321 (or 217314 counting only the distinct ones).

The product of its (nonzero) digits is 294, while the sum is 20.

The square root of 21730700 is about 4661.6198901240. The cubic root of 21730700 is about 279.0559190426.

The spelling of 21730700 in words is "twenty-one million, seven hundred thirty thousand, seven hundred".