61735721 has 16 divisors (see below), whose sum is σ = 68276880. Its totient is φ = 55572480.

The previous prime is 61735717. The next prime is 61735727. The reversal of 61735721 is 12753716.

It can be written as a sum of positive squares in 8 ways, for example, as 8970025 + 52765696 = 2995^2 + 7264^2 .

It is a cyclic number.

It is not a de Polignac number, because 61735721 - 2² = 61735717 is a prime.

It is a super-2 number, since 2×61735721² = 7622598494779682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61735727) 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, 37565 + ... + 39173.

It is an arithmetic number, because the mean of its divisors is an integer number (4267305).

Almost surely, 2^61735721 is an apocalyptic number.

61735721 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

61735721 is a deficient number, since it is larger than the sum of its proper divisors (6541159).

61735721 is a wasteful number, since it uses less digits than its factorization.

61735721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1724.

The product of its digits is 8820, while the sum is 32.

The square root of 61735721 is about 7857.2082192087. The cubic root of 61735721 is about 395.2260010956.

The spelling of 61735721 in words is "sixty-one million, seven hundred thirty-five thousand, seven hundred twenty-one".