21223221477 has 4 divisors (see below), whose sum is σ = 28297628640. Its totient is φ = 14148814316.

The previous prime is 21223221469. The next prime is 21223221493. The reversal of 21223221477 is 77412232212.

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 not a de Polignac number, because 21223221477 - 2³ = 21223221469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21223229477) 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, 3537203577 + ... + 3537203582.

It is an arithmetic number, because the mean of its divisors is an integer number (7074407160).

Almost surely, 2^21223221477 is an apocalyptic number.

It is an amenable number.

21223221477 is a deficient number, since it is larger than the sum of its proper divisors (7074407163).

21223221477 is an equidigital number, since it uses as much as digits as its factorization.

21223221477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7074407162.

The product of its digits is 18816, while the sum is 33.

Adding to 21223221477 its reverse (77412232212), we get a palindrome (98635453689).

The spelling of 21223221477 in words is "twenty-one billion, two hundred twenty-three million, two hundred twenty-one thousand, four hundred seventy-seven".