72031421 has 18 divisors (see below), whose sum is σ = 92109150. Its totient is φ = 56123760.

The previous prime is 72031411. The next prime is 72031439. The reversal of 72031421 is 12413027.

It can be written as a sum of positive squares in only one way, i.e., 71740900 + 290521 = 8470^2 + 539^2 .

It is not a de Polignac number, because 72031421 - 2¹⁰ = 72030397 is a prime.

It is a super-2 number, since 2×72031421² = 10377051222558482, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 72031393 and 72031402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72031411) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 146 + ... + 12003.

It is an arithmetic number, because the mean of its divisors is an integer number (5117175).

Almost surely, 2^72031421 is an apocalyptic number.

It is an amenable number.

72031421 is a deficient number, since it is larger than the sum of its proper divisors (20077729).

72031421 is a wasteful number, since it uses less digits than its factorization.

72031421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12185 (or 12167 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 72031421 is about 8487.1326724637. The cubic root of 72031421 is about 416.0772727665.

Adding to 72031421 its reverse (12413027), we get a palindrome (84444448).

The spelling of 72031421 in words is "seventy-two million, thirty-one thousand, four hundred twenty-one".