21421480477 has 2 divisors, whose sum is σ = 21421480478. Its totient is φ = 21421480476.

The previous prime is 21421480429. The next prime is 21421480607. The reversal of 21421480477 is 77408412412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16319807001 + 5101673476 = 127749^2 + 71426^2 .

It is a cyclic number.

It is not a de Polignac number, because 21421480477 - 2³¹ = 19273996829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21421480177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710740238 + 10710740239.

It is an arithmetic number, because the mean of its divisors is an integer number (10710740239).

Almost surely, 2^21421480477 is an apocalyptic number.

It is an amenable number.

21421480477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21421480477 is an equidigital number, since it uses as much as digits as its factorization.

21421480477 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 100352, while the sum is 40.

Adding to 21421480477 its reverse (77408412412), we get a palindrome (98829892889).

The spelling of 21421480477 in words is "twenty-one billion, four hundred twenty-one million, four hundred eighty thousand, four hundred seventy-seven".