21277619801 has 2 divisors, whose sum is σ = 21277619802. Its totient is φ = 21277619800.

The previous prime is 21277619791. The next prime is 21277619807. The reversal of 21277619801 is 10891677212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14060267776 + 7217352025 = 118576^2 + 84955^2 .

It is a cyclic number.

It is not a de Polignac number, because 21277619801 - 2¹⁸ = 21277357657 is a prime.

It is not a weakly prime, because it can be changed into another prime (21277619807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10638809900 + 10638809901.

It is an arithmetic number, because the mean of its divisors is an integer number (10638809901).

Almost surely, 2^21277619801 is an apocalyptic number.

It is an amenable number.

21277619801 is a deficient number, since it is larger than the sum of its proper divisors (1).

21277619801 is an equidigital number, since it uses as much as digits as its factorization.

21277619801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84672, while the sum is 44.

The spelling of 21277619801 in words is "twenty-one billion, two hundred seventy-seven million, six hundred nineteen thousand, eight hundred one".