21053756 has 6 divisors (see below), whose sum is σ = 36844080. Its totient is φ = 10526876.

The previous prime is 21053741. The next prime is 21053783. The reversal of 21053756 is 65735012.

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, 2631716 + ... + 2631723.

It is an arithmetic number, because the mean of its divisors is an integer number (6140680).

Almost surely, 2^21053756 is an apocalyptic number.

It is an amenable number.

21053756 is a deficient number, since it is larger than the sum of its proper divisors (15790324).

21053756 is a wasteful number, since it uses less digits than its factorization.

21053756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5263443 (or 5263441 counting only the distinct ones).

The product of its (nonzero) digits is 6300, while the sum is 29.

The square root of 21053756 is about 4588.4372067186. The cubic root of 21053756 is about 276.1276277339.

Adding to 21053756 its reverse (65735012), we get a palindrome (86788768).

The spelling of 21053756 in words is "twenty-one million, fifty-three thousand, seven hundred fifty-six".