21142577 has 8 divisors (see below), whose sum is σ = 22991976. Its totient is φ = 19360512.

The previous prime is 21142531. The next prime is 21142613. The reversal of 21142577 is 77524112.

It can be written as a sum of positive squares in 4 ways, for example, as 7311616 + 13830961 = 2704^2 + 3719^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21142577 - 2¹⁰ = 21141553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21142477) 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, 16178 + ... + 17435.

It is an arithmetic number, because the mean of its divisors is an integer number (2873997).

Almost surely, 2^21142577 is an apocalyptic number.

It is an amenable number.

21142577 is a deficient number, since it is larger than the sum of its proper divisors (1849399).

21142577 is a wasteful number, since it uses less digits than its factorization.

21142577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33667.

The product of its digits is 3920, while the sum is 29.

The square root of 21142577 is about 4598.1058056552. The cubic root of 21142577 is about 276.5153894688.

Adding to 21142577 its reverse (77524112), we get a palindrome (98666689).

The spelling of 21142577 in words is "twenty-one million, one hundred forty-two thousand, five hundred seventy-seven".