21429677 has 4 divisors (see below), whose sum is σ = 21586236. Its totient is φ = 21273120.

The previous prime is 21429671. The next prime is 21429691. The reversal of 21429677 is 77692412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4405801 + 17023876 = 2099^2 + 4126^2 .

It is a cyclic number.

It is not a de Polignac number, because 21429677 - 2⁶ = 21429613 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21429677.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21429671) 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, 78074 + ... + 78347.

It is an arithmetic number, because the mean of its divisors is an integer number (5396559).

Almost surely, 2^21429677 is an apocalyptic number.

It is an amenable number.

21429677 is a deficient number, since it is larger than the sum of its proper divisors (156559).

21429677 is a wasteful number, since it uses less digits than its factorization.

21429677 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156558.

The product of its digits is 42336, while the sum is 38.

The square root of 21429677 is about 4629.2199126851. The cubic root of 21429677 is about 277.7613888583.

The spelling of 21429677 in words is "twenty-one million, four hundred twenty-nine thousand, six hundred seventy-seven".