72198551 has 4 divisors (see below), whose sum is σ = 73215504. Its totient is φ = 71181600.

The previous prime is 72198523. The next prime is 72198559. The reversal of 72198551 is 15589127.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72198551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72198559) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 508370 + ... + 508511.

It is an arithmetic number, because the mean of its divisors is an integer number (18303876).

Almost surely, 2^72198551 is an apocalyptic number.

72198551 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

72198551 is a deficient number, since it is larger than the sum of its proper divisors (1016953).

72198551 is a wasteful number, since it uses less digits than its factorization.

72198551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1016952.

The product of its digits is 25200, while the sum is 38.

The square root of 72198551 is about 8496.9730492688. The cubic root of 72198551 is about 416.3988235588.

The spelling of 72198551 in words is "seventy-two million, one hundred ninety-eight thousand, five hundred fifty-one".