21491152 has 10 divisors (see below), whose sum is σ = 41639138. Its totient is φ = 10745568.

The previous prime is 21491149. The next prime is 21491189. The reversal of 21491152 is 25119412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 16842816 + 4648336 = 4104^2 + 2156^2 .

It is a super-2 number, since 2×21491152² = 923739228574208, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 671583 + ... + 671614.

Almost surely, 2^21491152 is an apocalyptic number.

It is an amenable number.

21491152 is a deficient number, since it is larger than the sum of its proper divisors (20147986).

21491152 is a wasteful number, since it uses less digits than its factorization.

21491152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1343205 (or 1343199 counting only the distinct ones).

The product of its digits is 720, while the sum is 25.

The square root of 21491152 is about 4635.8550451885. The cubic root of 21491152 is about 278.0267386251.

The spelling of 21491152 in words is "twenty-one million, four hundred ninety-one thousand, one hundred fifty-two".