21700016 has 20 divisors (see below), whose sum is σ = 45278352. Its totient is φ = 10015296.

The previous prime is 21700001. The next prime is 21700039. The reversal of 21700016 is 61000712.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21699967 and 21700003.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51956 + ... + 52371.

Almost surely, 2^21700016 is an apocalyptic number.

21700016 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21700016 is an abundant number, since it is smaller than the sum of its proper divisors (23578336).

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

21700016 is a wasteful number, since it uses less digits than its factorization.

21700016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104348 (or 104342 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21700016 is about 4658.3275968957. The cubic root of 21700016 is about 278.9245137784.

Adding to 21700016 its reverse (61000712), we get a palindrome (82700728).

The spelling of 21700016 in words is "twenty-one million, seven hundred thousand, sixteen".