81766020 has 48 divisors (see below), whose sum is σ = 261652608. Its totient is φ = 18689280.

The previous prime is 81766019. The next prime is 81766031. The reversal of 81766020 is 2066718.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96921 + ... + 97760.

It is an arithmetic number, because the mean of its divisors is an integer number (5451096).

Almost surely, 2^81766020 is an apocalyptic number.

It is an amenable number.

81766020 is an abundant number, since it is smaller than the sum of its proper divisors (179886588).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81766020 is a wasteful number, since it uses less digits than its factorization.

81766020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194700 (or 194698 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 81766020 is about 9042.4565246398. The cubic root of 81766020 is about 434.0345346881.

It can be divided in two parts, 8176 and 6020, that added together give a triangular number (14196 = T₁₆₈).

The spelling of 81766020 in words is "eighty-one million, seven hundred sixty-six thousand, twenty".