21521294 has 4 divisors (see below), whose sum is σ = 32281944. Its totient is φ = 10760646.

The previous prime is 21521263. The next prime is 21521299. The reversal of 21521294 is 49212512.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5380322 + ... + 5380325.

It is an arithmetic number, because the mean of its divisors is an integer number (8070486).

Almost surely, 2^21521294 is an apocalyptic number.

21521294 is a deficient number, since it is larger than the sum of its proper divisors (10760650).

21521294 is a wasteful number, since it uses less digits than its factorization.

21521294 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10760649.

The product of its digits is 1440, while the sum is 26.

The square root of 21521294 is about 4639.1048705542. The cubic root of 21521294 is about 278.1566582487.

The spelling of 21521294 in words is "twenty-one million, five hundred twenty-one thousand, two hundred ninety-four".