21497670 has 32 divisors (see below), whose sum is σ = 57327840. Its totient is φ = 5732640.

The previous prime is 21497669. The next prime is 21497677. The reversal of 21497670 is 7679412.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21497677) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39541 + ... + 40080.

It is an arithmetic number, because the mean of its divisors is an integer number (1791495).

Almost surely, 2^21497670 is an apocalyptic number.

21497670 is an abundant number, since it is smaller than the sum of its proper divisors (35830170).

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

21497670 is a wasteful number, since it uses less digits than its factorization.

21497670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79637 (or 79631 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 21497670 is about 4636.5579905788. The cubic root of 21497670 is about 278.0548431385.

The spelling of 21497670 in words is "twenty-one million, four hundred ninety-seven thousand, six hundred seventy".