21221012 has 6 divisors (see below), whose sum is σ = 37136778. Its totient is φ = 10610504.

The previous prime is 21221003. The next prime is 21221021. The reversal of 21221012 is 21012212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21221003) and next prime (21221021).

It can be written as a sum of positive squares in only one way, i.e., 21215236 + 5776 = 4606^2 + 76^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21220984 and 21221002.

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, 2652623 + ... + 2652630.

It is an arithmetic number, because the mean of its divisors is an integer number (6189463).

Almost surely, 2^21221012 is an apocalyptic number.

It is an amenable number.

21221012 is a deficient number, since it is larger than the sum of its proper divisors (15915766).

21221012 is a wasteful number, since it uses less digits than its factorization.

21221012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5305257 (or 5305255 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21221012 is about 4606.6269655790. The cubic root of 21221012 is about 276.8569075918.

Adding to 21221012 its reverse (21012212), we get a palindrome (42233224).

It can be divided in two parts, 212 and 21012, that multiplied together give a palindrome (4454544).

The spelling of 21221012 in words is "twenty-one million, two hundred twenty-one thousand, twelve".