55720981 has 8 divisors (see below), whose sum is σ = 57961728. Its totient is φ = 53508000.

The previous prime is 55720979. The next prime is 55721011. The reversal of 55720981 is 18902755.

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

It is a cyclic number.

It is not a de Polignac number, because 55720981 - 2¹ = 55720979 is a prime.

It is a super-2 number, since 2×55720981² = 6209655447204722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55720981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55720921) 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, 2800 + ... + 10921.

It is an arithmetic number, because the mean of its divisors is an integer number (7245216).

Almost surely, 2^55720981 is an apocalyptic number.

It is an amenable number.

55720981 is a deficient number, since it is larger than the sum of its proper divisors (2240747).

55720981 is a wasteful number, since it uses less digits than its factorization.

55720981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13883.

The product of its (nonzero) digits is 25200, while the sum is 37.

The square root of 55720981 is about 7464.6487526206. The cubic root of 55720981 is about 381.9497686205.

The spelling of 55720981 in words is "fifty-five million, seven hundred twenty thousand, nine hundred eighty-one".