21630036 has 12 divisors (see below), whose sum is σ = 50470112. Its totient is φ = 7210008.

The previous prime is 21630031. The next prime is 21630061. The reversal of 21630036 is 63003612.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21630036² = 935716914722592, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21629994 and 21630021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21630031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 901240 + ... + 901263.

Almost surely, 2^21630036 is an apocalyptic number.

It is an amenable number.

21630036 is an abundant number, since it is smaller than the sum of its proper divisors (28840076).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21630036 is a wasteful number, since it uses less digits than its factorization.

21630036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1802510 (or 1802508 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 21.

The square root of 21630036 is about 4650.8102519884. The cubic root of 21630036 is about 278.6243579712.

Adding to 21630036 its reverse (63003612), we get a palindrome (84633648).

The spelling of 21630036 in words is "twenty-one million, six hundred thirty thousand, thirty-six".