21629870 has 16 divisors (see below), whose sum is σ = 39763008. Its totient is φ = 8467680.

The previous prime is 21629863. The next prime is 21629887. The reversal of 21629870 is 7892612.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21629870.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22541 + ... + 23480.

It is an arithmetic number, because the mean of its divisors is an integer number (2485188).

Almost surely, 2^21629870 is an apocalyptic number.

21629870 is a deficient number, since it is larger than the sum of its proper divisors (18133138).

21629870 is a wasteful number, since it uses less digits than its factorization.

21629870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46075.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 21629870 is about 4650.7924056014. The cubic root of 21629870 is about 278.6236452006.

The spelling of 21629870 in words is "twenty-one million, six hundred twenty-nine thousand, eight hundred seventy".