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, and also an emirpimes, since its reverse is a distinct semiprime: 75551207 = 401 ⋅188407.
It is a cyclic number.
It is a Duffinian number.
It is a congruent number.
Almost surely, 270215557 is an apocalyptic number.
It is an amenable number.
70215557 is a wasteful number, since it uses less digits than its factorization.
70215557 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 25338.
The square root of 70215557 is about 8379.4723580903. The cubic root of 70215557 is about 412.5511307296.
The spelling of 70215557 in words is "seventy million, two hundred fifteen thousand, five hundred fifty-seven".