21021003877 has 2 divisors, whose sum is σ = 21021003878. Its totient is φ = 21021003876.

The previous prime is 21021003827. The next prime is 21021003901. The reversal of 21021003877 is 77830012012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20758758241 + 262245636 = 144079^2 + 16194^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021003877 - 2⁷ = 21021003749 is a prime.

It is a super-2 number, since 2×21021003877² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021003827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510501938 + 10510501939.

It is an arithmetic number, because the mean of its divisors is an integer number (10510501939).

Almost surely, 2^21021003877 is an apocalyptic number.

It is an amenable number.

21021003877 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021003877 is an equidigital number, since it uses as much as digits as its factorization.

21021003877 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4704, while the sum is 31.

Adding to 21021003877 its reverse (77830012012), we get a palindrome (98851015889).

The spelling of 21021003877 in words is "twenty-one billion, twenty-one million, three thousand, eight hundred seventy-seven".