61975781 has 4 divisors (see below), whose sum is σ = 70829472. Its totient is φ = 53122092.

The previous prime is 61975747. The next prime is 61975787. The reversal of 61975781 is 18757916.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61975781 is a prime.

It is a super-2 number, since 2×61975781² = 7681994861119922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61975787) 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, 4426835 + ... + 4426848.

It is an arithmetic number, because the mean of its divisors is an integer number (17707368).

Almost surely, 2^61975781 is an apocalyptic number.

It is an amenable number.

61975781 is a deficient number, since it is larger than the sum of its proper divisors (8853691).

61975781 is an equidigital number, since it uses as much as digits as its factorization.

61975781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8853690.

The product of its digits is 105840, while the sum is 44.

The square root of 61975781 is about 7872.4698157567. The cubic root of 61975781 is about 395.7376186772.

The spelling of 61975781 in words is "sixty-one million, nine hundred seventy-five thousand, seven hundred eighty-one".