651221157 has 4 divisors (see below), whose sum is σ = 868294880. Its totient is φ = 434147436.

The previous prime is 651221141. The next prime is 651221161. The reversal of 651221157 is 751122156.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 651221157 - 2⁴ = 651221141 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 (651221117) 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, 108536857 + ... + 108536862.

It is an arithmetic number, because the mean of its divisors is an integer number (217073720).

Almost surely, 2^651221157 is an apocalyptic number.

It is an amenable number.

651221157 is a deficient number, since it is larger than the sum of its proper divisors (217073723).

651221157 is a wasteful number, since it uses less digits than its factorization.

651221157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217073722.

The product of its digits is 4200, while the sum is 30.

The square root of 651221157 is about 25519.0351894424. The cubic root of 651221157 is about 866.7812346733.

Subtracting 651221157 from its reverse (751122156), we obtain a palindrome (99900999).

The spelling of 651221157 in words is "six hundred fifty-one million, two hundred twenty-one thousand, one hundred fifty-seven".