51720019 has 8 divisors (see below), whose sum is σ = 55756512. Its totient is φ = 47691840.

The previous prime is 51719981. The next prime is 51720029. The reversal of 51720019 is 91002715.

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 51720019 - 2¹³ = 51711827 is a prime.

It is a super-2 number, since 2×51720019² = 5349920730720722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51719975 and 51720002.

It is not an unprimeable number, because it can be changed into a prime (51720029) 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, 18327 + ... + 20959.

It is an arithmetic number, because the mean of its divisors is an integer number (6969564).

Almost surely, 2^51720019 is an apocalyptic number.

51720019 is a deficient number, since it is larger than the sum of its proper divisors (4036493).

51720019 is a wasteful number, since it uses less digits than its factorization.

51720019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4157.

The product of its (nonzero) digits is 630, while the sum is 25.

The square root of 51720019 is about 7191.6631595202. The cubic root of 51720019 is about 372.5800173431.

The spelling of 51720019 in words is "fifty-one million, seven hundred twenty thousand, nineteen".