61531501 has 2 divisors, whose sum is σ = 61531502. Its totient is φ = 61531500.

The previous prime is 61531499. The next prime is 61531541. The reversal of 61531501 is 10513516.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54375876 + 7155625 = 7374^2 + 2675^2 .

It is a cyclic number.

It is not a de Polignac number, because 61531501 - 2¹ = 61531499 is a prime.

It is a super-2 number, since 2×61531501² = 7572251230626002, which contains 22 as substring.

Together with 61531499, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61531541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30765750 + 30765751.

It is an arithmetic number, because the mean of its divisors is an integer number (30765751).

Almost surely, 2^61531501 is an apocalyptic number.

It is an amenable number.

61531501 is a deficient number, since it is larger than the sum of its proper divisors (1).

61531501 is an equidigital number, since it uses as much as digits as its factorization.

61531501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 450, while the sum is 22.

The square root of 61531501 is about 7844.2017439635. The cubic root of 61531501 is about 394.7897209033.

The spelling of 61531501 in words is "sixty-one million, five hundred thirty-one thousand, five hundred one".