81903657 has 16 divisors (see below), whose sum is σ = 121669632. Its totient is φ = 48581520.

The previous prime is 81903641. The next prime is 81903673. The reversal of 81903657 is 75630918.

It is an interprime number because it is at equal distance from previous prime (81903641) and next prime (81903673).

It is not a de Polignac number, because 81903657 - 2⁴ = 81903641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81903677) 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, 24853 + ... + 27954.

It is an arithmetic number, because the mean of its divisors is an integer number (7604352).

Almost surely, 2^81903657 is an apocalyptic number.

It is an amenable number.

81903657 is a deficient number, since it is larger than the sum of its proper divisors (39765975).

81903657 is a wasteful number, since it uses less digits than its factorization.

81903657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52868.

The product of its (nonzero) digits is 45360, while the sum is 39.

The square root of 81903657 is about 9050.0639224262. The cubic root of 81903657 is about 434.2779354016.

The spelling of 81903657 in words is "eighty-one million, nine hundred three thousand, six hundred fifty-seven".