145637737721 has 6 divisors (see below), whose sum is σ = 169415327610. Its totient is φ = 124832346576.

The previous prime is 145637737711. The next prime is 145637737723. The reversal of 145637737721 is 127737736541.

It can be written as a sum of positive squares in only one way, i.e., 89542183696 + 56095554025 = 299236^2 + 236845^2 .

It is not a de Polignac number, because 145637737721 - 2⁶ = 145637737657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (145637737723) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1486099316 + ... + 1486099413.

It is an arithmetic number, because the mean of its divisors is an integer number (28235887935).

Almost surely, 2^145637737721 is an apocalyptic number.

It is an amenable number.

145637737721 is a deficient number, since it is larger than the sum of its proper divisors (23777589889).

145637737721 is an equidigital number, since it uses as much as digits as its factorization.

145637737721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2972198743 (or 2972198736 counting only the distinct ones).

The product of its digits is 5186160, while the sum is 53.

The spelling of 145637737721 in words is "one hundred forty-five billion, six hundred thirty-seven million, seven hundred thirty-seven thousand, seven hundred twenty-one".