81420497 has 16 divisors (see below), whose sum is σ = 88687872. Its totient is φ = 74453760.

The previous prime is 81420439. The next prime is 81420503. The reversal of 81420497 is 79402418.

It is a cyclic number.

It is not a de Polignac number, because 81420497 - 2¹⁰ = 81419473 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81420407) 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, 144338 + ... + 144900.

It is an arithmetic number, because the mean of its divisors is an integer number (5542992).

Almost surely, 2^81420497 is an apocalyptic number.

It is an amenable number.

81420497 is a deficient number, since it is larger than the sum of its proper divisors (7267375).

81420497 is a wasteful number, since it uses less digits than its factorization.

81420497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 808.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 81420497 is about 9023.3307043464. The cubic root of 81420497 is about 433.4222972504.

The spelling of 81420497 in words is "eighty-one million, four hundred twenty thousand, four hundred ninety-seven".