21090632 has 32 divisors (see below), whose sum is σ = 41791680. Its totient is φ = 9958080.

The previous prime is 21090631. The next prime is 21090647. The reversal of 21090632 is 23609012.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a junction number, because it is equal to n+sod(n) for n = 21090598 and 21090607.

It is not an unprimeable number, because it can be changed into a prime (21090631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14582 + ... + 15962.

It is an arithmetic number, because the mean of its divisors is an integer number (1305990).

Almost surely, 2^21090632 is an apocalyptic number.

It is an amenable number.

21090632 is a deficient number, since it is larger than the sum of its proper divisors (20701048).

21090632 is a wasteful number, since it uses less digits than its factorization.

21090632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1493 (or 1489 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 21090632 is about 4592.4538103284. The cubic root of 21090632 is about 276.2887477299.

Adding to 21090632 its reverse (23609012), we get a palindrome (44699644).

The spelling of 21090632 in words is "twenty-one million, ninety thousand, six hundred thirty-two".