84723781 has 2 divisors, whose sum is σ = 84723782. Its totient is φ = 84723780.

The previous prime is 84723773. The next prime is 84723829. The reversal of 84723781 is 18732748.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73102500 + 11621281 = 8550^2 + 3409^2 .

It is a cyclic number.

It is not a de Polignac number, because 84723781 - 2³ = 84723773 is a prime.

It is a super-2 number, since 2×84723781² = 14356238133871922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84723701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42361890 + 42361891.

It is an arithmetic number, because the mean of its divisors is an integer number (42361891).

Almost surely, 2^84723781 is an apocalyptic number.

It is an amenable number.

84723781 is a deficient number, since it is larger than the sum of its proper divisors (1).

84723781 is an equidigital number, since it uses as much as digits as its factorization.

84723781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75264, while the sum is 40.

The square root of 84723781 is about 9204.5521889987. The cubic root of 84723781 is about 439.2061806186.

The spelling of 84723781 in words is "eighty-four million, seven hundred twenty-three thousand, seven hundred eighty-one".