21997460 has 24 divisors (see below), whose sum is σ = 46435200. Its totient is φ = 8753184.

The previous prime is 21997447. The next prime is 21997463. The reversal of 21997460 is 6479912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21997463) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1217 + ... + 6743.

It is an arithmetic number, because the mean of its divisors is an integer number (1934800).

Almost surely, 2^21997460 is an apocalyptic number.

21997460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21997460 is an abundant number, since it is smaller than the sum of its proper divisors (24437740).

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

21997460 is a wasteful number, since it uses less digits than its factorization.

21997460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5735 (or 5733 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 21997460 is about 4690.1449870979. The cubic root of 21997460 is about 280.1931490446.

It can be divided in two parts, 219 and 97460, that added together give a palindrome (97679).

The spelling of 21997460 in words is "twenty-one million, nine hundred ninety-seven thousand, four hundred sixty".