91215285 has 64 divisors (see below), whose sum is σ = 178371072. Its totient is φ = 38854656.

The previous prime is 91215209. The next prime is 91215287. The reversal of 91215285 is 58251219.

It is not a de Polignac number, because 91215285 - 2¹² = 91211189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91215287) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 244359 + ... + 244731.

It is an arithmetic number, because the mean of its divisors is an integer number (2787048).

Almost surely, 2^91215285 is an apocalyptic number.

It is an amenable number.

91215285 is a deficient number, since it is larger than the sum of its proper divisors (87155787).

91215285 is a wasteful number, since it uses less digits than its factorization.

91215285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 542.

The product of its digits is 7200, while the sum is 33.

The square root of 91215285 is about 9550.6693482708. The cubic root of 91215285 is about 450.1485682285.

The spelling of 91215285 in words is "ninety-one million, two hundred fifteen thousand, two hundred eighty-five".