21075464 has 8 divisors (see below), whose sum is σ = 39516510. Its totient is φ = 10537728.

The previous prime is 21075463. The next prime is 21075473. The reversal of 21075464 is 46457012.

It can be written as a sum of positive squares in only one way, i.e., 13468900 + 7606564 = 3670^2 + 2758^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21075463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1317209 + ... + 1317224.

Almost surely, 2^21075464 is an apocalyptic number.

It is an amenable number.

21075464 is a deficient number, since it is larger than the sum of its proper divisors (18441046).

21075464 is a wasteful number, since it uses less digits than its factorization.

21075464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2634439 (or 2634435 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 21075464 is about 4590.8021085645. The cubic root of 21075464 is about 276.2224978934. Note that the first 3 decimals are identical.

The spelling of 21075464 in words is "twenty-one million, seventy-five thousand, four hundred sixty-four".