81725070 has 32 divisors (see below), whose sum is σ = 224160768. Its totient is φ = 18679968.

The previous prime is 81725009. The next prime is 81725071. The reversal of 81725070 is 7052718.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81725071) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 194374 + ... + 194793.

It is an arithmetic number, because the mean of its divisors is an integer number (7005024).

Almost surely, 2^81725070 is an apocalyptic number.

81725070 is an abundant number, since it is smaller than the sum of its proper divisors (142435698).

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

81725070 is a wasteful number, since it uses less digits than its factorization.

81725070 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389184.

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 81725070 is about 9040.1919227415. The cubic root of 81725070 is about 433.9620649663.

Adding to 81725070 its reverse (7052718), we get a palindrome (88777788).

The spelling of 81725070 in words is "eighty-one million, seven hundred twenty-five thousand, seventy".