91249015801821 has 32 divisors (see below), whose sum is σ = 129762508861440. Its totient is φ = 56837432537856.

The previous prime is 91249015801819. The next prime is 91249015801837. The reversal of 91249015801821 is 12810851094219.

It is not a de Polignac number, because 91249015801821 - 2¹ = 91249015801819 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91249015801871) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3155341 + ... + 13872786.

It is an arithmetic number, because the mean of its divisors is an integer number (4055078401920).

Almost surely, 2^{91249015801821} is an apocalyptic number.

It is an amenable number.

91249015801821 is a deficient number, since it is larger than the sum of its proper divisors (38513493059619).

91249015801821 is a wasteful number, since it uses less digits than its factorization.

91249015801821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17028913.

The product of its (nonzero) digits is 414720, while the sum is 51.

The spelling of 91249015801821 in words is "ninety-one trillion, two hundred forty-nine billion, fifteen million, eight hundred one thousand, eight hundred twenty-one".