21221492 has 6 divisors (see below), whose sum is σ = 37137618. Its totient is φ = 10610744.

The previous prime is 21221471. The next prime is 21221503. The reversal of 21221492 is 29412212.

It can be written as a sum of positive squares in only one way, i.e., 21031396 + 190096 = 4586^2 + 436^2 .

It is a congruent number.

It is an unprimeable number.

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, 2652683 + ... + 2652690.

It is an arithmetic number, because the mean of its divisors is an integer number (6189603).

Almost surely, 2^21221492 is an apocalyptic number.

It is an amenable number.

21221492 is a deficient number, since it is larger than the sum of its proper divisors (15916126).

21221492 is a wasteful number, since it uses less digits than its factorization.

21221492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5305377 (or 5305375 counting only the distinct ones).

The product of its digits is 576, while the sum is 23.

The square root of 21221492 is about 4606.6790641415. The cubic root of 21221492 is about 276.8589949933.

The spelling of 21221492 in words is "twenty-one million, two hundred twenty-one thousand, four hundred ninety-two".