2135977721 has 2 divisors, whose sum is σ = 2135977722. Its totient is φ = 2135977720.

The previous prime is 2135977709. The next prime is 2135977741. The reversal of 2135977721 is 1277795312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1918002025 + 217975696 = 43795^2 + 14764^2 .

It is a cyclic number.

It is not a de Polignac number, because 2135977721 - 2¹⁴ = 2135961337 is a prime.

It is not a weakly prime, because it can be changed into another prime (2135977741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1067988860 + 1067988861.

It is an arithmetic number, because the mean of its divisors is an integer number (1067988861).

Almost surely, 2^2135977721 is an apocalyptic number.

It is an amenable number.

2135977721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2135977721 is an equidigital number, since it uses as much as digits as its factorization.

2135977721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 185220, while the sum is 44.

The square root of 2135977721 is about 46216.6390058819. The cubic root of 2135977721 is about 1287.8508615640.

The spelling of 2135977721 in words is "two billion, one hundred thirty-five million, nine hundred seventy-seven thousand, seven hundred twenty-one".