21053777777 has 16 divisors (see below), whose sum is σ = 22146803712. Its totient is φ = 19989244800.

The previous prime is 21053777749. The next prime is 21053777819. The reversal of 21053777777 is 77777735012.

It is a cyclic number.

It is not a de Polignac number, because 21053777777 - 2¹² = 21053773681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21053777677) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1825493 + ... + 1836989.

It is an arithmetic number, because the mean of its divisors is an integer number (1384175232).

Almost surely, 2^21053777777 is an apocalyptic number.

It is an amenable number.

21053777777 is a deficient number, since it is larger than the sum of its proper divisors (1093025935).

21053777777 is a wasteful number, since it uses less digits than its factorization.

21053777777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12728.

The product of its (nonzero) digits is 3529470, while the sum is 53.

The spelling of 21053777777 in words is "twenty-one billion, fifty-three million, seven hundred seventy-seven thousand, seven hundred seventy-seven".