81159420 has 24 divisors (see below), whose sum is σ = 227246544. Its totient is φ = 21642496.

The previous prime is 81159413. The next prime is 81159427. The reversal of 81159420 is 2495118.

81159420 = 1026² + 1027² + ... + 1097².

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81159413) and next prime (81159427).

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 (81159427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 676269 + ... + 676388.

It is an arithmetic number, because the mean of its divisors is an integer number (9468606).

Almost surely, 2^81159420 is an apocalyptic number.

It is an amenable number.

81159420 is an abundant number, since it is smaller than the sum of its proper divisors (146087124).

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

81159420 is a wasteful number, since it uses less digits than its factorization.

81159420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1352669 (or 1352667 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 81159420 is about 9008.8523131418. The cubic root of 81159420 is about 432.9585411541.

The spelling of 81159420 in words is "eighty-one million, one hundred fifty-nine thousand, four hundred twenty".