61720581 has 8 divisors (see below), whose sum is σ = 88624480. Its totient is φ = 37981872.

The previous prime is 61720579. The next prime is 61720583. The reversal of 61720581 is 18502716.

It is an interprime number because it is at equal distance from previous prime (61720579) and next prime (61720583).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 61720581 - 2¹ = 61720579 is a prime.

It is a super-2 number, since 2×61720581² = 7618860237955122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61720583) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 791251 + ... + 791328.

It is an arithmetic number, because the mean of its divisors is an integer number (11078060).

Almost surely, 2^61720581 is an apocalyptic number.

It is an amenable number.

61720581 is a deficient number, since it is larger than the sum of its proper divisors (26903899).

61720581 is a wasteful number, since it uses less digits than its factorization.

61720581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1582595.

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 61720581 is about 7856.2447136020. The cubic root of 61720581 is about 395.1936901915.

The spelling of 61720581 in words is "sixty-one million, seven hundred twenty thousand, five hundred eighty-one".