21382497 has 6 divisors (see below), whose sum is σ = 30885842. Its totient is φ = 14254992.

The previous prime is 21382463. The next prime is 21382499. The reversal of 21382497 is 79428312.

It can be written as a sum of positive squares in only one way, i.e., 20034576 + 1347921 = 4476^2 + 1161^2 .

It is not a de Polignac number, because 21382497 - 2⁷ = 21382369 is a prime.

It is a super-2 number, since 2×21382497² = 914422355910018, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21382499) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1187908 + ... + 1187925.

Almost surely, 2^21382497 is an apocalyptic number.

It is an amenable number.

21382497 is a deficient number, since it is larger than the sum of its proper divisors (9503345).

21382497 is a wasteful number, since it uses less digits than its factorization.

21382497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2375839 (or 2375836 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21382497 is about 4624.1212138092. The cubic root of 21382497 is about 277.5573974284.

The spelling of 21382497 in words is "twenty-one million, three hundred eighty-two thousand, four hundred ninety-seven".