91970744021 has 16 divisors (see below), whose sum is σ = 100941516144. Its totient is φ = 83271711744.

The previous prime is 91970744017. The next prime is 91970744071. The reversal of 91970744021 is 12044707919.

It can be written as a sum of positive squares in 8 ways, for example, as 9848379121 + 82122364900 = 99239^2 + 286570^2 .

It is not a de Polignac number, because 91970744021 - 2² = 91970744017 is a prime.

It is a super-3 number, since 3×91970744021³ (a number of 34 digits) contains 333 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 (91970744011) 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, 2861975 + ... + 2893931.

It is an arithmetic number, because the mean of its divisors is an integer number (6308844759).

Almost surely, 2^91970744021 is an apocalyptic number.

It is an amenable number.

91970744021 is a deficient number, since it is larger than the sum of its proper divisors (8970772123).

91970744021 is a wasteful number, since it uses less digits than its factorization.

91970744021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36200.

The product of its (nonzero) digits is 127008, while the sum is 44.

The spelling of 91970744021 in words is "ninety-one billion, nine hundred seventy million, seven hundred forty-four thousand, twenty-one".