2051221311 has 12 divisors (see below), whose sum is σ = 3004606800. Its totient is φ = 1348220160.

The previous prime is 2051221307. The next prime is 2051221331. The reversal of 2051221311 is 1131221502.

2051221311 is a `hidden beast` number, since 20 + 512 + 2 + 131 + 1 = 666.

It is not a de Polignac number, because 2051221311 - 2² = 2051221307 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2051221331) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1604386 + ... + 1605663.

It is an arithmetic number, because the mean of its divisors is an integer number (250383900).

Almost surely, 2^2051221311 is an apocalyptic number.

2051221311 is a deficient number, since it is larger than the sum of its proper divisors (953385489).

2051221311 is a wasteful number, since it uses less digits than its factorization.

2051221311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3210126 (or 3210123 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 2051221311 is about 45290.4108062623. The cubic root of 2051221311 is about 1270.5863147238.

Adding to 2051221311 its reverse (1131221502), we get a palindrome (3182442813).

The spelling of 2051221311 in words is "two billion, fifty-one million, two hundred twenty-one thousand, three hundred eleven".