21542077 has 8 divisors (see below), whose sum is σ = 22938552. Its totient is φ = 20160000.

The previous prime is 21542071. The next prime is 21542083. The reversal of 21542077 is 77024512.

It is an interprime number because it is at equal distance from previous prime (21542071) and next prime (21542083).

It can be written as a sum of positive squares in 4 ways, for example, as 556516 + 20985561 = 746^2 + 4581^2 .

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 21542077 - 2¹⁵ = 21509309 is a prime.

It is a super-2 number, since 2×21542077² = 928122162947858, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21542071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 424 + ... + 6577.

It is an arithmetic number, because the mean of its divisors is an integer number (2867319).

Almost surely, 2^21542077 is an apocalyptic number.

It is an amenable number.

21542077 is a deficient number, since it is larger than the sum of its proper divisors (1396475).

21542077 is a wasteful number, since it uses less digits than its factorization.

21542077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7199.

The product of its (nonzero) digits is 3920, while the sum is 28.

The square root of 21542077 is about 4641.3443095724. The cubic root of 21542077 is about 278.2461675808.

Adding to 21542077 its reverse (77024512), we get a palindrome (98566589).

The spelling of 21542077 in words is "twenty-one million, five hundred forty-two thousand, seventy-seven".