70720537 has 4 divisors (see below), whose sum is σ = 70764580. Its totient is φ = 70676496.

The previous prime is 70720519. The next prime is 70720543. The reversal of 70720537 is 73502707.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73502707 = 761 ⋅96587.

It can be written as a sum of positive squares in 2 ways, for example, as 18071001 + 52649536 = 4251^2 + 7256^2 .

It is a cyclic number.

It is not a de Polignac number, because 70720537 - 2¹⁵ = 70687769 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 70720499 and 70720508.

It is not an unprimeable number, because it can be changed into a prime (70720547) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19518 + ... + 22855.

It is an arithmetic number, because the mean of its divisors is an integer number (17691145).

Almost surely, 2^70720537 is an apocalyptic number.

It is an amenable number.

70720537 is a deficient number, since it is larger than the sum of its proper divisors (44043).

70720537 is a wasteful number, since it uses less digits than its factorization.

70720537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44042.

The product of its (nonzero) digits is 10290, while the sum is 31.

The square root of 70720537 is about 8409.5503446974. The cubic root of 70720537 is about 413.5377716695.

The spelling of 70720537 in words is "seventy million, seven hundred twenty thousand, five hundred thirty-seven".