81261275 has 24 divisors (see below), whose sum is σ = 108234144. Its totient is φ = 60300800.

The previous prime is 81261251. The next prime is 81261281. The reversal of 81261275 is 57216218.

It is not a de Polignac number, because 81261275 - 2²² = 77066971 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28829 + ... + 31521.

It is an arithmetic number, because the mean of its divisors is an integer number (4509756).

Almost surely, 2^81261275 is an apocalyptic number.

81261275 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

81261275 is a deficient number, since it is larger than the sum of its proper divisors (26972869).

81261275 is a wasteful number, since it uses less digits than its factorization.

81261275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2791 (or 2786 counting only the distinct ones).

The product of its digits is 6720, while the sum is 32.

The square root of 81261275 is about 9014.5035914353. The cubic root of 81261275 is about 433.1395862995.

It can be divided in two parts, 812 and 61275, that multiplied together give a triangular number (49755300 = T₉₉₇₅).

The spelling of 81261275 in words is "eighty-one million, two hundred sixty-one thousand, two hundred seventy-five".