91520023021 has 8 divisors (see below), whose sum is σ = 104601559680. Its totient is φ = 78440298288.

The previous prime is 91520022991. The next prime is 91520023037. The reversal of 91520023021 is 12032002519.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91520023021 - 2⁵ = 91520022989 is a prime.

It is a super-2 number, since 2×91520023021² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91520023421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 342961 + ... + 548326.

It is an arithmetic number, because the mean of its divisors is an integer number (13075194960).

Almost surely, 2^91520023021 is an apocalyptic number.

It is an amenable number.

91520023021 is a deficient number, since it is larger than the sum of its proper divisors (13081536659).

91520023021 is a wasteful number, since it uses less digits than its factorization.

91520023021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 905963.

The product of its (nonzero) digits is 1080, while the sum is 25.

The spelling of 91520023021 in words is "ninety-one billion, five hundred twenty million, twenty-three thousand, twenty-one".