21697480 has 32 divisors (see below), whose sum is σ = 55794240. Its totient is φ = 7439040.

The previous prime is 21697477. The next prime is 21697531. The reversal of 21697480 is 8479612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38466 + ... + 39025.

It is an arithmetic number, because the mean of its divisors is an integer number (1743570).

Almost surely, 2^21697480 is an apocalyptic number.

21697480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21697480 is an abundant number, since it is smaller than the sum of its proper divisors (34096760).

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

21697480 is a wasteful number, since it uses less digits than its factorization.

21697480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77509 (or 77505 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 21697480 is about 4658.0553882495. The cubic root of 21697480 is about 278.9136477322.

The spelling of 21697480 in words is "twenty-one million, six hundred ninety-seven thousand, four hundred eighty".