71772021 has 16 divisors (see below), whose sum is σ = 106529920. Its totient is φ = 47757600.

The previous prime is 71771993. The next prime is 71772023. The reversal of 71772021 is 12027717.

It is not a de Polignac number, because 71772021 - 2⁵ = 71771989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71772023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14016 + ... + 18438.

It is an arithmetic number, because the mean of its divisors is an integer number (6658120).

Almost surely, 2^71772021 is an apocalyptic number.

It is an amenable number.

71772021 is a deficient number, since it is larger than the sum of its proper divisors (34757899).

71772021 is a wasteful number, since it uses less digits than its factorization.

71772021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5033 (or 5027 counting only the distinct ones).

The product of its (nonzero) digits is 1372, while the sum is 27.

The square root of 71772021 is about 8471.8369318584. The cubic root of 71772021 is about 415.5772119929.

Adding to 71772021 its reverse (12027717), we get a palindrome (83799738).

The spelling of 71772021 in words is "seventy-one million, seven hundred seventy-two thousand, twenty-one".