21997709452 has 12 divisors (see below), whose sum is σ = 38959799256. Its totient is φ = 10866338240.

The previous prime is 21997709449. The next prime is 21997709467. The reversal of 21997709452 is 25490779912.

It is a happy number.

It is a super-2 number, since 2×21997709452² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21997709393 and 21997709402.

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, 33128749 + ... + 33129412.

It is an arithmetic number, because the mean of its divisors is an integer number (3246649938).

Almost surely, 2^21997709452 is an apocalyptic number.

It is an amenable number.

21997709452 is a deficient number, since it is larger than the sum of its proper divisors (16962089804).

21997709452 is a wasteful number, since it uses less digits than its factorization.

21997709452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66258248 (or 66258246 counting only the distinct ones).

The product of its (nonzero) digits is 2857680, while the sum is 55.

The spelling of 21997709452 in words is "twenty-one billion, nine hundred ninety-seven million, seven hundred nine thousand, four hundred fifty-two".