21798029 has 12 divisors (see below), whose sum is σ = 25371612. Its totient is φ = 18648960.

The previous prime is 21798017. The next prime is 21798047. The reversal of 21798029 is 92089712.

21798029 = 363² + 364² + ... + 483².

It can be written as a sum of positive squares in 2 ways, for example, as 7562500 + 14235529 = 2750^2 + 3773^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21798029 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21797983 and 21798001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3242 + ... + 7355.

It is an arithmetic number, because the mean of its divisors is an integer number (2114301).

Almost surely, 2^21798029 is an apocalyptic number.

It is an amenable number.

21798029 is a deficient number, since it is larger than the sum of its proper divisors (3573583).

21798029 is a wasteful number, since it uses less digits than its factorization.

21798029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10636 (or 10625 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 21798029 is about 4668.8359362908. The cubic root of 21798029 is about 279.3438248607.

The spelling of 21798029 in words is "twenty-one million, seven hundred ninety-eight thousand, twenty-nine".