21231077 has 4 divisors (see below), whose sum is σ = 24264096. Its totient is φ = 18198060.

The previous prime is 21231029. The next prime is 21231107. The reversal of 21231077 is 77013212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21231077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231577) 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, 1516499 + ... + 1516512.

It is an arithmetic number, because the mean of its divisors is an integer number (6066024).

Almost surely, 2^21231077 is an apocalyptic number.

It is an amenable number.

21231077 is a deficient number, since it is larger than the sum of its proper divisors (3033019).

21231077 is an equidigital number, since it uses as much as digits as its factorization.

21231077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3033018.

The product of its (nonzero) digits is 588, while the sum is 23.

The square root of 21231077 is about 4607.7192839842. The cubic root of 21231077 is about 276.9006712028.

Adding to 21231077 its reverse (77013212), we get a palindrome (98244289).

The spelling of 21231077 in words is "twenty-one million, two hundred thirty-one thousand, seventy-seven".