21256010 has 8 divisors (see below), whose sum is σ = 38260836. Its totient is φ = 8502400.

The previous prime is 21255973. The next prime is 21256013. The reversal of 21256010 is 1065212.

It can be written as a sum of positive squares in 2 ways, for example, as 17480761 + 3775249 = 4181^2 + 1943^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21256010² = 903635922240200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21256010.

It is not an unprimeable number, because it can be changed into a prime (21256013) 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 in 3 ways as a sum of consecutive naturals, for example, 1062791 + ... + 1062810.

Almost surely, 2^21256010 is an apocalyptic number.

21256010 is a deficient number, since it is larger than the sum of its proper divisors (17004826).

21256010 is a wasteful number, since it uses less digits than its factorization.

21256010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2125608.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21256010 is about 4610.4240585872. The cubic root of 21256010 is about 277.0090228047.

The spelling of 21256010 in words is "twenty-one million, two hundred fifty-six thousand, ten".