21077829 has 6 divisors (see below), whose sum is σ = 30445766. Its totient is φ = 14051880.

The previous prime is 21077803. The next prime is 21077831. The reversal of 21077829 is 92877012.

It can be written as a sum of positive squares in only one way, i.e., 14265729 + 6812100 = 3777^2 + 2610^2 .

It is not a de Polignac number, because 21077829 - 2⁹ = 21077317 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21077793 and 21077802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21077839) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1170982 + ... + 1170999.

Almost surely, 2^21077829 is an apocalyptic number.

It is an amenable number.

21077829 is a deficient number, since it is larger than the sum of its proper divisors (9367937).

21077829 is a wasteful number, since it uses less digits than its factorization.

21077829 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2341987 (or 2341984 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 21077829 is about 4591.0596815986. The cubic root of 21077829 is about 276.2328296829.

The spelling of 21077829 in words is "twenty-one million, seventy-seven thousand, eight hundred twenty-nine".