51721623 has 12 divisors (see below), whose sum is σ = 76531728. Its totient is φ = 33639840.

The previous prime is 51721619. The next prime is 51721627. The reversal of 51721623 is 32612715.

It is a happy number.

51721623 is a `hidden beast` number, since 5 + 17 + 21 + 623 = 666.

It is an interprime number because it is at equal distance from previous prime (51721619) and next prime (51721627).

It is not a de Polignac number, because 51721623 - 2² = 51721619 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51721627) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 69715 + ... + 70452.

It is an arithmetic number, because the mean of its divisors is an integer number (6377644).

Almost surely, 2^51721623 is an apocalyptic number.

51721623 is a deficient number, since it is larger than the sum of its proper divisors (24810105).

51721623 is a wasteful number, since it uses less digits than its factorization.

51721623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140214 (or 140211 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 51721623 is about 7191.7746766706. The cubic root of 51721623 is about 372.5838689282.

The spelling of 51721623 in words is "fifty-one million, seven hundred twenty-one thousand, six hundred twenty-three".