87721811 has 2 divisors, whose sum is σ = 87721812. Its totient is φ = 87721810.

The previous prime is 87721807. The next prime is 87721877. The reversal of 87721811 is 11812778.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 87721811 - 2² = 87721807 is a prime.

It is a super-2 number, since 2×87721811² = 15390232250239442, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (87721801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43860905 + 43860906.

It is an arithmetic number, because the mean of its divisors is an integer number (43860906).

Almost surely, 2^87721811 is an apocalyptic number.

87721811 is a deficient number, since it is larger than the sum of its proper divisors (1).

87721811 is an equidigital number, since it uses as much as digits as its factorization.

87721811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6272, while the sum is 35.

The square root of 87721811 is about 9365.9922592323. The cubic root of 87721811 is about 444.3268212323.

The spelling of 87721811 in words is "eighty-seven million, seven hundred twenty-one thousand, eight hundred eleven".