81749267901 has 80 divisors (see below), whose sum is σ = 146043368064. Its totient is φ = 44593151616.

The previous prime is 81749267879. The next prime is 81749267923. The reversal of 81749267901 is 10976294718.

81749267901 is a `hidden beast` number, since 8 + 1 + 7 + 492 + 67 + 90 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (81749267879) and next prime (81749267923).

It is not a de Polignac number, because 81749267901 - 2⁷ = 81749267773 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81749267101) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1075126 + ... + 1148648.

Almost surely, 2^81749267901 is an apocalyptic number.

81749267901 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

81749267901 is a deficient number, since it is larger than the sum of its proper divisors (64294100163).

81749267901 is a wasteful number, since it uses less digits than its factorization.

81749267901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73632 (or 73623 counting only the distinct ones).

The product of its (nonzero) digits is 1524096, while the sum is 54.

The spelling of 81749267901 in words is "eighty-one billion, seven hundred forty-nine million, two hundred sixty-seven thousand, nine hundred one".